STUDY ON FILLER IN RESIN ABRASIVE TOOLS

HENAN UNIVERSITY OF TECHNOLOGY

Abstract

Keywords: Resin abrasive, FIller, Phenolic resin, polyimide resin, Superabrasive grinding wheel
Contents
1. Introduction
2. Bond
2.1 Phenolic resin
2.3 Phenolic resin bonds
2.4 Polyimide resin
2.5 Liquid resin
2.6 Powder resin
2.7 Epoxy or urethane resin
2.8 . Other bond systems
2.9 Rubber
2.10. Shellac
2.11. Silicate
3. The abrasive
3.1. Abrasive materials
3.2. Characteristic of abrasive and materials ground
3.3. Super hard abrasive resin grinding wheel
3.4. Diamond (natural and synthesised)
Resin-bonded tools
12. Additives for abrasive materials
13. Grinding wheel specification: super abrasives
14. Super abrasives
15. Fillers in resin bonds
16. The grinding tool molding, curing, pore
17. Filler additive in the manufacturing of resin tool
18. Resin bonded diamond wheels with copper and silicon fillers
19. Conclusion
Reference

3. Resin bond wheels

2
Introduction
Resin abrasive is made of resin binder, auxiliary material and abrasive particles
together to form having certain rigidity (strength and hardness) of the grinding tool.
It is widely used in steel, automotive, aerospace, machine tools, instrumentation,
chemical, construction and other aspects of grinding, and particularly in grinding
and polishing areas with excellent processing characteristics, so it is irreplaceable in
the grinding tool. Among diamond abrasive with binding agent, the resin binder of
the total amount of 60 ~ 70%, and among CBN abrasives binding agent, the resin
binder also accounted for about 40%. With the development of polymer materials in
chemical industry, synthetic resin is widely used in abrasive industry, and in some
developed countries; the industrial production of resin grinding tool is increasing.
[doi:10.4028/www.scientific.net/AMR.842.18]
Resin bonds for abrasive tools consist of single resins or a resin combination with or
without fillers (see Sect 3.1.3 “Fillers in Resin Bonds”). The resin itself is typically
manufactured by esterification or soaping of organic compounds. Filler material has
not only the task to reinforce the bonding in toughness, heat resistance, strength, and
breakage safety, but also to support the grinding process as secondary abrasive
[Fillers in Resin Bonds” RWTHedition) Barbara Linke (auth.)]- Life Cycle and
Sustainability.pdf ] Thompson appl. No 429,996
Grinding grade is often modified by altering the time and temperature of the cure, or
it may be altered by adjusting the proportions of the filler/resin ratio, or by changing
the resin. This invention utilizes neither of these known techniques. The grinding
grade is adjusted by modifying the filler composition. Fillers are bond modifiers.
They are substances that are mixed with the bond material, in this case, an organic
resin, to modify a bond for a particular purpose. As part of the bond a filler is
functionally made non abrasive regardless of its composition. The most common
practice for accomplishing this is to make the filler material finer than the abrasive
grit although it is also possible to judiciously choose a filler material which is not
capable of abrading a particular material.
In terms of binder, mainly about phenolic resin:
(1). Resin quality stability problems, especially the level of free phenol in the resin.
Excessive free phenol content will accelerate the cracking of the resin after heating
and hardening of the resin wheel and affect the strength of the grinding wheel;
(2). The binder’s particle is too thick or too fine:
It is generally believed that the fine grain is benefitial to uniform distribution of the
binder. If the grain is too coarse, the molding material is not easily mixed
uniformly, which affects thehardness and strength of the grinding wheel. Even for
the coarse-grained resin sheet cutting wheel and the cymbal grinding wheel, the size
of the binder (resin powder) selected should be finer than 320#[
https://www.zhongsen-refractory.com/en/news/problems-in-manufacturing-resin-
grinding-wheel] Resin abrasive tool has common problems in the known as binders
for abrasive particles since as early as 1909, as taught by Leo H. Baekeland in U.S.
Pat. No. 942,808 it is poor control of the resin binder and poor heat resistance,
which leading to high temperature generated during the grinding or grinding
abrasive wear of the large amount of heat is large, seriaosly affect the grinding
efficiency and cured resin was brittle, lack of thoughtness, so that there are many

3
scratches on the surface of the grinding and cutting tool. In the order to improve the
resin abrsive production and solve these problems, an addition to abrasive, resin and
hardener, we often add appropriate amount of auxiliary materials in the resin binder.
Filler is solid a additivies as of the most important additivies of resin binder with
reinforcement, hard, thoughening, enhanced finish, it also can increase wear
resistance and improve water resistance and heat resistance functions.

Common resin and filler content percentage in grinding wheels

Table 3.1 Common resin and filler content percentage in grinding wheels [COLL88,
p. 897, GARZ00, p. 323]

1. THE BOND
Givot et al. Patent No.: US 9,180,573 B2 Bonded abrasive articles have abrasive
particles bonded together by a bonding medium. Bonded abrasives include, for
example, Stones, hones, grinding wheels, and cut-off wheels. The bonding medium
is typically an organic resin, but may also be an inorganic material Such as a
ceramic or glass (i.e., vitreous bonds).
The particular bonding resin employed is not critical. Any of the standard resins
employed for making grinding wheels are useful. Obviously strength and heat
resistance are desirable properties. The well-known cross linked resins such as
phenol-aldehyde resins, melamine aldehyde resins, urea-aldehyde resins, polyester
resins, and epoxy resins, including the epox-novolacs, may all be used, and
conventional modifiers, plasticizers, and fillers may be employed. Fairly recently
new essentially linear polymers as well as thermoset polymers (such as thermoset
polymides disclosed in French Pat. 1,455,514) have been introduced which have
utility in bonding abrasive grains. Any of the known synthetic resins useful in
making coated or bonded abrasives may be employed in the present invention.
Obviously, strength and heat resistance are necessary properties. Part of the filler
content may consist of conventional particulate fillers such as silicon carbide. Siqui
et al.Appl. No.163,976 These resins, like the crosslinked resins dis cussed above,
are infusible, as opposed to the morecommon thermoplastic linear polymers having
definite softening ranges and which are reversibly softenable. Examples of such
resins, having utility in making abrasive tools, are given in U.S. Pat. No. 3,329,489
(poly benzimidazole), and U.S. Pat.Nos. 3,295,940 and 3,385,684 (polymides).
Polysulfide resins such as disclosed in U.S. Pat. No. 3,303,170 and polypyrrones
may also be employed. For use in making coated abrasive discs or belts liquid resin

4
systems may be preferred, while for bonded abrasives solid powdered resins can be
used.
Thompson. Appl. No. 429,996. 1975 It is an object of the invention to provide a
filler com position for an organic resin bonded abrasive article which utilizes
particles of a material that is harder than the metal, in combination with the metal to
accelerate the degradation of the bond. The customary way to insure that the proper
wheel is available for a particular grinding operation is to modify the strength of the
bond by adding inorganic inert fillers to the bonding material-the organic resin -and
develop a grade system. This is well-known in the grinding wheel industry, and
requires little explanation. Wheels at the “hard' end of the grade system have an
extremely tenacious bond, which holds each grain firmly throughout its maximum
useful life. These wheels, when used on the proper operation, give long life, and the
greatest economy.

1.1. THE RESIN BONDS

Resin bonds are generally classified into organic, nonorganic and hybrid. Organic
bonds are divided into resin and rubber. Resin bonds have four types: phenol resin,
polyimide resin, epoxy or urethane resin and shellac. Nonorganic bonds are
separated into vitrified bonds and metallic bonds. There are two types of metallic
bonds: single-layer and multi-layer. Single-layer bonds can be electroplated and
brazed. Multi-layer bonds can be sintered and infiltrated.
The bond / book Principles of Modern Grinding Technology/, Phenolic Resins: A
Century of ProgressL pilato shar nom 307-335 huudas ,Asashi diamond industrial
Co.,Ltd magazine
The bond role is holding individual abrasives together. Phenol resin is commonly
used to resinoid grinding wheels. Resin is a member of plastic. There has 2 types of
resin: thermosetting resin and thermoplastic resin.
Thermoplastic resin such as polyethylene, vinyl chloride resin, polypropylene, ABS
resin and PET softens when it’s heated and becomes moldable. Thermosetting
resin such as phenol resin, urea resin, epoxy resin, melamine resin, unsaturated
polyester resin and polyurethane hardens when it’s heated and can not be remolded.
It has higher chemical and heat resistance. It is molded and processed easily. Resin
bonds for abrasive tools are done by single resins or a resin combination with or
without fillers.
Since the creation of resin bonds, there have been many types that have
improved over time for example: phenolic resin, polyimide resin, Epoxy resin,
Midified phenolic resin, Phenolic-Epoxy, Boron-modified phenolic resin,
Water-soluble resin. S.Y.Luo 1998
Phenolic resin-based diamond composites have been used widely for manufacturing
such important abrasive tools as grinding wheels, cut-off wheels, polishing pad,
pellets, etc. The performance of these tools during operation depends significantly
on the wear behavior between the diamond grits and the resin bond. Furthermore,
the wear modes of the diamond are also influenced by the specification of the
abrasive tool, the operating conditions, and the properties of the work piece
materials. Under dry machining conditions, high temperatures are developed
instantaneously between the diamond particle and the workpiece, thereby causing

5
thermal damage of the resin and the workpiece, which can lead to the wheel
wearing rapidly. In modern manufacturing, there has four well-spread employed
bond components are: resin, vitrified, metallic and electroplated types used to
improve the cured characteristics of the resin layer. Additionally, solvents may be
utilized to alter the characteristics of the resin material in the uncured State.
Table.1 Compares hardness, strength and elasticity of resin bond
Mechanic Resin Vetrifie Metalli
property bond d bond c bond
Brinell 228 380 278
hardness
(HB)
Rupture 1046 1243 2073
strength
(psi)
Elasticity 173.50 599.500 792.000
(psi) 0

Table.1 Compares hardness, strength and elasticity of resin bond, vitrified bond and
metallic bond. Hardness of vitrified bond is the highest. Metallic bond has the
highest strength and elasticity than other two types.[1]
Linke, Barbara. "Manufacturing and sustainability of bonding systems for grinding
tools." Production Engineering 10.3 (2016): 265-276.
https://link.springer.com/article/10.1007%2Fs11740-016-0668-5

Understanding how each kind of grind wheel is made is important. Manufacturing

process governs grinding wheels properties, procedures of recovery and sharpening,
are the most dominant points for grinding wheel effectiveness. Grinding wheels
with resin bond are produced by mixing convenient amounts of phenolic resin or
polyamide and fillers with the suitable weight and size of the CBN abrasive with
metallic layer.
The most important grinding wheels characteristics of grinding wheels with resin
bond are the following:
- It can be used for many kinds of applications
- It is possible in a great many shapes and sizes
- It can be used for refrigerated and dry machining
- It has good cutting qualities.[1]

6
Figure.1 6.Kuchle, A. (2009). Manufacturing processes: Grinding, honing, lapping.
Springer.
Stockwell, B. H. (1986). Die Metallurgie der Metallwerkzeuge. Industrie
Diamanten 1. Rundschau, 1(86), 31-35
https://sci-hub.tw/https://doi.org/10.1002/14356007.a01_001
2.Winter, M., Ibbotson, S., Kara, S., & Herrmann, C. (2015). Life cycle assessment
of cubic boron nitride grinding wheels. Journal of Cleaner Production, 107, 707-
721.doi:10.1016/j.jclepro.2015.05.088
3.Gardziella, A., Pilato, L. A., & Knop, A. (2013). Phenolic resins: chemistry,
applications, standardization, safety and ecology. Springer Science & Business
Media.
4. Asami M, Santorelli M (2010) Abrasives, Chapter 13. In: Pilato L(ed) Phenolic
resins: a century of progress. Springer, New York,pp 307–343 Webster and Tricard
2004 2005
It is recognized that in practice, the wear of the abrasive tool can proceed only as
fast as the bond fracture occurs. Prior to bond fracture, pieces of the abrasive are
lost by fracture of the grain and to a lesser extent by attritions wear (Rowe 2009;
Jackson and Hitchiner 2013). The structure and composition of the abrasive tool is
therefore complex and has been presented in the form of a “grinding wheel phase
diagram” or “triple-coordinate system” to enable visibility of the interactions that
can occur between the volume Vk of grains, volume Vp of pores, and the volume
VB of the bond. The regions for conventional abrasives and super abrasives such as
cBN are shown below. Figure 2 shows the triple-coordinate system for the
interaction enabled by the bond, namely, the ability to structure the abrasive. Klocke
2009 Klocke F (2009) Manufacturing processes 2, grinding, honing, lapping,
RWTH edition. Springer, Berlin/ Heidelbergmentions the following
limits:Conventional grinding tools: VKmax = 68%. VKmin = 40%, VBmax = 25%
and VBmin = 5%, cBN grinding tools: VKmax = 55%. VKmin = 18%, VBmax =
48% and VBmin = 10%.
Moving outside the limits highlighted in Fig. 2 above for conventional grinding
tools requires special measures to be undertaken, for example, the inclusion of
burnout materials to create larger pores, or hot pressing to close the bond structure

7
and reduce or eliminate pores. The standard classifications of the bonded abrasives
place high emphasis on the bond type, and categories of grade and structure are also
a function of the bonding system.

Bonding Materials for Abrasive Tools, Fig. 2

Triple-coordinate system for the interaction
enabled by the bond
Hammarstrom et al.1997 Appl. No.: 689,575
Resin-bonded abrasive articles such as grinding wheels arc typically produced
by blending discredit abrasive particles with a liquid binder material and a
powdered resin, and then pressing the mixture under appropriate thermal conditions.
Other constituents can be included in the mixtures fillers, curing agents, wetting
agents, and various metal powders. An aging period which allows for solvation of
the dry portion of the mixture with the liquid resin is usually required before
pressing. Westberg et al Appl . No 16 / 095 , 514
Typical types of bonding agents used to make bonded abrasive tools are :
resinoid, vitrified, and metal. Bonded abrasive tools include, for example grinding
wheels, cut - off - wheels , grindstones, honing rings, etc A bonding agent of cut -
off tools is typically a cured organic binder . Resin bonded tools utilize an organic
binder system based on , e . g . , a phenolic resin and fillers such as metal sulfides ,
metal oxides or metal halogenides binder . Resin bonded tools utilize an organic
binder system based on , e .g . , a phenolic resin and fillers such as metal sulfides ,
metal oxides or metal halogenides .
1.2 METAL BONDS
Lei Guo Study of the Influence of Nanosized Filler on the UV-Curable Resin
Bonded Diamond In industry, two primary types of diamond grain is commonly
selected as the abrasive for manufacturing of diamond abrasive tools: metal bond
diamond grain and resin bond diamond grain. The former one, metal bond diamond
grain is the powder with high concentrate particles, accurate size and irregular
shape. It is always used for high performance metal bond tools to ensure excellent
abrasive action and tight particle size distribution. Abrasive tools with metal bond

8
diamond could benefit from its aggressive stock removal and good surface finish
properties.

Metal bond is a binding material made of metallic powders of copper, tin, iron, etc.
it has excellent grit retention and wear resistance compared to other wheels. The
metallic sintered bond systems are made from bronze in the copper-tin alloy with an
alloy composition range between 60:40 and 85:15 and additional fillers 11]
Marinescu, I.D., Hitchiner, M., Uhlmann, E., Rowe, W.B., Inasaki, I., 2007.
Handbook of achining with grinding wheels. CRC Press, Taylor & Francis Group,
Florida, USA. 11. this article as: Winter M, Ibbotson S, Kara S, Herrmann C, Life
cycle assessment of cubic boron nitride grinding wheels, Journal of Cleaner
Production (2015), doi: 10.1016/j.jclepro.2015.05.088.
Metal bonds are used for superabrasives. Diamonds or CBN grains can be applied in
a single layer onto a metal disk or as a multi-layer abrasive in a sintered cast iron
bond. Single-layer superabrasive wheels that employ larger grains give durability in
service for grinding the hardest materials. The setting operation and wheel mounting
must therefore be carried out with extreme accuracy. Despite the difficulties and
expense, electroplated CBN wheels have been highly successful for high-speed
precision grinding, high removal rates, and long wheel life. Metal bond diamond
wheels are often used wet for grinding ceramics and brittle abrasive materials.
Multi-layer wheels using very small diamond grains are used to produce very high
accuracy and low surface roughness. A new electrolytic in-process dressing system
of grinding (ELID grinding) allows multi-layer wheels bonded in a conductive
metal to be dressed to maintain sharpness and form. Rowe, W. B.
(2013). Principles of modern grinding technology. William Andrew.]
Menard, J. C., & Thibault, N. W. (2000). Abrasives. Ullmann's Encyclopedia of
Industrial Chemistry
The abrasive most often bonded with metal is manufactured diamond, but the use of
cubic boron nitride (CBN) in metal bonds is expected to increase very significantly.
Three types of metal-bonded products are made:
1. Those in which the abrasive zone is bonded directly to the core by a heating
process;
2. Those in which segments or rims are produced and then attached to the core or
steel blade afterward;
3. Those bonded by electroplating. For the fifirst type, a core or preform is placed in
a mold, and the abrasive-metal mix added and then pressed. After being stripped
from the mold, the body usually is sintered to maximum density, or it may be
sintered to controlled porosity followed by infifiltration with a liquid metal, such as
a silver solder. Alternatively, the product may be hot pressed in a graphite mold.
Bond compositions vary greatly. Commonly used ones include bronzes, various
cobalt and nickel alloys, steels, and cemented carbides. Maturing temperatures vary
from 500 C for bronzes to 1200 C for cemented carbides. Firing is in neutral or

9
reducing atmospheres. In general softer bonds are used with hard, dense work
materials, whereas harder ones are used to grind relatively soft but abrasive
materials. For example, bronze bonds commonly are used on dense alumina,
cemented carbides, and quartz crystals, whereas carbide bonds often are used to
groove concrete highways and cut sandstones. In the case of rims and segments,
similar bonds, manufacturing methods, and firing temperatures are employed. In the
production of diamond blades for use in the construction industry, segments have
been attached to the steel center by brazing. However, laser welding, introduced in
1982, has permitted a much higher bonding strength, virtually eliminating loss of
segments because of weakening of the joint from the heat generated during the
cutting operations. Electroplated products normally have a rigid core, a nickel bond,
and a single layer of either diamond or CBN. Examples are: diamond-coated
mounted points and discs used by dentists, relatively inexpensive diamond-coated
wheels for offhand sharpening of carbide tools, and wheels of complicated shapes
coated with diamond or CBN used for form grinding of work pieces, where great
precision can be attained because of little or no tool wear.
Characteristics of metal bond wheels

1. Metal bond wheels are divided into three major types which is superior
in grinding ability cobalt-type which is superior in wheel life and steel
type which stands in the middle in grinding capability.
2. Metal bond wheels have excellent grit retention and wear resistance
compared to resin bond wheels and vitrified bond wheels, it has long
wheel life in processing difficult to machine materials such as glass,
ceramic, semiconductor electron materials.
3. Metal bond wheels also can be used for electrolytic grinding and
electrical discharge grinding (EDM), using its electric conductivity.

4.

1.3 ELECTROPLATED BOND

Electrical wheels, bring stable performance in grinding accuracy, grinding ability,
and wheel life they have an excellent reputation in variety of applications.The
electroplated bond system enfolds a process where a single layer of cBN abrasive
grains is directly bonded to the wheel hub by an electro deposition of nickel or a

10
 nickel alloy Davis, J.R., 1995. ASM Specialty Handbook Tool Materials, ASM
International, Materials Park, Ohio, USA. 9. Please cite this article as: Winter M,
Ibbotson S, Kara S, Herrmann C, Life cycle assessment of cubic boron nitride
grinding wheels, Journal of Cleaner Production (2015), doi:
10.1016/j.jclepro.2015.05.088.

Characteristics of electroplated wheels:

1. They are constant in grinding ability, and can be suited for many materials because
of the amount of the abrasive protruding from the bond.
2. They are capable of holding from at low cost and can be, made in short period of
time.
3. They are best suited to produce small volume in wide range of categories. Wheels
life is shorter than other bonds because electroplated wheels are typically a single
layer of abrasive material.
4. If the core is metallic, the super abrasive can be electroplated to various forms.
Therefore it is used not only as a grinding wheel but us as wear resistant tools.
5. The consumed abrasive can be stripped and replayed using the existing core,
providing it is not damaged.

Rubber wheels tend to be used for cut-off wheels where the requirement is for
durability. They wear rapidly at high temperatures. Rubber wheels are also used for
control wheels in centreless grinding.

11
Shellac wheels are used for finishing operations. Being softer and more flexible,
they polish the surface with less risk of scratching. [Rowe, W. B.
(2013). Principles of modern grinding technology. William Andrew.] p. 40

Figure 1.6 Resin-bonded tools. (Courtesy of EHWA Diamond Ind. Co., Ltd.)
Konstanty, J. (2011). Powder metallurgy diamond tools. Elsevier.

2. BONDING MATERIALS FOR ABRASIVE TOOLS

The bonding material is the material that secures the abrasive grains relative to each
other in order to form the shape and structural integrity of the abrasive tool such as a
grinding wheel, bonded abrasive segment, or abrasive belt.
Bonding Materials for Abrasive Tools, Fig. 1 Bonded abrasive showing pores, chip,
bonds, and showing wear evolution
Theory and Application
The DIN 8589: 2003 classifies processes such as grinding, belt grinding, honing,
lapping, free abrasive grinding, and abrasive blast cutting under the grouping of
“machining with geometrically undefined cutting edges.” A further clustering of the
aforementioned processes can also be presented, namely, that of machining with
bonded abrasives encompassing grinding, belt grinding, and honing, with the
remaining processes largely falling under the category of free or un bonded abrasive
machining. Therefore, it is clear that the science underpinning bonding materials is
core to the development of bonded abrasive tools (Jackson and Davim 2011 DIN
4000-132: (2011) Sachmerkmal-Listen – Teil 132: Schleifwerkzeuge mit Diamant
oder Bornitrid mit Bohrung [Tabular layouts of properties – Part 132: Super
abrasive products with bore]. Beuth, Berlin (in German)
2.1 PHENOLIC RESIN
Harris et al. Appl. No.: 688,532 Phenol-formaldehyde condensation resins have
been During the years to follow, phenol-formaldehyde resins became the basis for a
sizeable segment of the polymer industry. Dozens of phenolic resins were de
veloped which were modifications of the two basic types. Powdered two-stage
resins became and are still available in which the molecular weight of the prepoly

12
mer varies. The hexamethylenetetramine content of these resins vary from 8% to as
high as 13% depending on the degree of cross-linking and thermal stability desired.
There are a large number of commercial two stage resins which have been modified
by the addition thereto of thermoplastic polymers such as polyvinyl alcohol,
polyvinyl butyral, or the like, the effect of such additions being to lower heat
resistance, which means softer grinding action when used as a binder for grinding
wheels. To produce a similar product, but one with less thermal susceptibility,
powdered one-stage resin has been blended with a hexamethylenetetramine
containing two-stage resin. There are powdered one-stage resins commercially
available but these are not widely used by the grinding wheel industry. One such
use however, is disclosed by G. J. Goepfert in U.S. Pat. No. 2,769,700 wherein a
powdered one-stage resin is utilized, in combination with a liquid one-stage resin, to
form a diamond abrasive containing grinding wheel. Although powdered one-stage
resins are not widely used by the grinding wheel industry, liquid one-stage resins
are liquid resins are used as so-called pick-up agents for the powdered bond which
is made up of powdered resin and usually a powdered filler material. The abrasive
grains are thoroughly wetted or coated with the liquid resin to which is then added,
the powdered bond. The conglomeration is then mixed until essentially all of the
powdered bond is picked up by the tacky coating of liquid resin on the abrasive
grain. The mixture is then formed and heat treated to cure both the liquid and
powdered phenol-formaldehyde resins. Phenol-formaldehyde polymers have been
and remain today the most widely used polymers for grinding wheel bonds. The
success of this material is due primarily to its high mechanical strength and
excellent resistance to thermal degradation as compared to other thermosetting
resins such as the unsaturated polyesters and the epoxy resins. However, there are
some grinding applications where these superior properties are a detriment, for
example in such grinding operations as polishing, and some precision grinding
operations, particularly where the metal may be heat sensitive. To satisfy this need
bonds were developed which were more heat sensitive than the phenol-
formaldehyde bonds discussed thus far.
Phenolic resins used in abrasive products. Phenolic bonds represent the largest
market segment for conventional grinding wheels after vitrified bonds, and
dominate the rough-grinding sector of the industry for snagging and cutoff
applications. The bonds consist of thermosetting resins and plasticizers, which are
cured around 150 to 200°C. The bond type was originally known as “Bakelite” and
for this reason still retains the letter “B” in most wheel specifications. Grade or
hardness is controlled to some extent by the plasticizer and use of fillers. Phenolic
resin divides into thermoplastic resin and thermosetting phenolic resin.
Thermoplastic phenolic resin is now widely used as bond in abrasive products H.
Min, Y.B. Ho, J.C. In: Ploymer vol.43 (2002), p.4437. The density of phenolic is
1.18-1.32g/cm3. Abrasive products using thermoplastic as bond has the virtue of
good elasticity, high strength, impact resistance, good self-sharpening, high
processing efficiency, etc. but it has many shortcoming, such as brittle, bond
strength not enough, low heat-resistance and abrasive wear too much T. Akihiro, U.
Kazunori, T. Aokichi, et al: Wear, Vol.257 (2004), p.1096. Especially in producing
abrasive diamond products to use phenolic resin as bond, it needs to process resin,
load mode, shape under high temperature and pressure and remold, etc. the

13
technology is complex. Several limitations are found in the practice. By mixing
abrasive grains with phenolic thermosetting resins and plasticizers produce resinoid-
bonded wheels, molding to form and curing at 150˚C-200˚C. The bond hardness
depends on the amount of plasticizer and addition of fillers. Heavy-duty grinding
operations use conventional abrasive resinoid wheels because of their high strength
and possibility to stand shock loads. Comparing to other resins, phenolic resin is
less high-priced and easier to mold.The phenolic resin bond for grinding wheels
holds (liquid phenolic resin-by its form, resole type by its chemical property) and
(powdered phenolic resin-by its form, novolak type-by its chemical property).
Further, phenolic resin bonds for super abrasives are enhanced by SiC grits and
solid lubricants. Phenolic resins are cured at around 150˚C to 200˚C through
polycondensation, hardening procedure
Characteristics of phenol resin:
- Firm to other chemicals and many solvents;
- Higher heat resistance than others;
- Less shrinkage after molding;
- Higher mechanical strength
Phenolic resin For superabrasive wheels, phenolic resin bonds represent the earliest,
and most popular, bond type particularly for diamond wheels and especially for
tool-room applications. The bonds were originally developed for diamond with the
introduction of carbide tooling in the 1940s. Their resilience made them optimal for
maintaining tight radii while withstanding the impact of interrupted cuts typical of
drill, hob, and broach grinding. To prevent localized temperature rise, the abrasive
is typically metal coated to act as a heat sink to dissipate the heat. In addition, high
volumes of copper or other metal fillers may be used to increase thermal
conductivity and heat dissipation. Not surprisingly, phenolic resin bonds were
quickly adopted with the introduction of CBN in 1969, and phenolic resin bonds
predominate for the steel tool industry [Craig 1991].[27]. Ellendman, M., ‘How
Coolants Affect the Performance of Resin-bonded Abrasive Wheels’, Machine and
Production Engineering, 115, No. 2975, 1969, p. 812.]. Lin, C. T., Lee, H. T., &
Chen, J. K. (2016). Preparation of vanadium‐modified phenolic resin/modified
zirconia composites and its applied properties in cubic boron nitride (cBN) grinding
wheels. Polymer Composites, 37(12), 3354-3364.
Generally, phenolic resins are produced by reacting phenol with formaldehyde in
the presence of a catalyst. Phenol is the most commonly used reagent for the source
of OH groups in the synthesis of phenolic resins. But we use bisphenol-F monomer
in this work, in view of the flexible methylene linkage between two phenylene
groups. The bisphenol-F-based phenolic resins may be less brittle than the
conventional one. The use of bisphenol-F for the preparation of phenolic resins is
rarely reported in literature [1J. Gao, L. Xia, and Y. Liu, Polym. Degrad. Stab., 83,
71 Phenolic resins are widely used in various industries because of their flame-
retardant behavior and high char yield after pyrolysis, high chemical resistance,
electrical insulation, thermal resistance, mechanical strength, adhesive property, and
dimensional stability [M. Lopez, M. Blanco, A. Vazquez, N. Gabilondo, A.
Arbelaiz, J.M. Echeverria, and I. Mondragon, Thermochim. Acta, 467, 73 (2008). 3.
J. Wang, H. Jiang, and N. Jiang, Thermochim. Acta, 496, 136 (2009). 4. C. Martin,
J. Ronda, and V. Cadiz, Polym. Sci. Part A: Polym. Chem., 44, 3503 (2006). 5.

14
H.H. Wu and P.P. Chu, Polym. Degrad. Stab., 95, 1849 (2010).2–5]. The
applications are as nose caps, binders for grinding tools, exit cones for rocket
nozzles, molding compounds, foundry materials, coatings, wood-like products, and
other composite materials with good thermal resistance and mechanical strength
Although phenolic resins have a wide range of applications, their thermal resistance
and brittle property still can be improved. So the modification of phenolic resins is
still being performed in many laboratories nowadays. In order to improve the
above-mentioned properties, phenolic resins are blended with various inorganic and
metal materials. Many studies reported the modification of phenolic resins by
introducing boron or molybdenum in their backbone chains to enhance its thermal
and mechanical properties. However, in the literature, the modification of phenolic
resin by introducing vanadium has not been reported until now. Therefore, in this
article, phenolic resin was modified by ammonium vanadate during the synthesis of
bisphenol-F-basedphenolic resin. In recently Bisphenol-F-based vanadium-phenolic
resin/modified zirconia (Bis-VPF/m-ZrO) composites were prepared by first
reacting ammonium vasnadate and phenolic resin, and then incorporating the
AEAPTMS-modified zirconia (m-ZrO). Thermal resistance and mechanical strength
of Bis-PF are significantly improved by treating with ammonium vanadate and m-
ZrO. The glass transition temperature, decomposition temperature at 10% weight
loss, and flexural strength of Bis-VPF/m-ZrO are 2898C, 5288C, and 95.7 MPa,
respectively, which are 1028C, 1088C, and 39.6 MPa higher than the corresponding
values of Bis-PF. Bis-VPF/m-ZrO exhibits superior properties to Bis-PF. This is
due to that ammonium vanadate reacted with phenolic hydroxyl groups of Bis-PF to
form cross-linked VAO bonds and the m-ZrO is well-dispersed and well adhered in
Bis-VPF/m-ZrO. SEM images of the Bis-VPF/m-ZrOs fractural surfaces show no
gaps or void between m-ZrO and Bis-VPF phases, which implies that m-ZrO has
strong physical bonding with Bis-VPF phase. Furthermore, the hygroscopic nature
of Bis-PF can be more diminished by reacting with ammonium vanadate and
incorporating with hydrophobic m-ZrO. In addition, Bis VPF/m-ZrO is a better
binding resin than the Bis-PF as evaluated by the grinding experiments with the
corresponding cBN grinding wheels.Menard, J. C., & Thibault, N. W. (2000).
Abrasives. Ullmann's Encyclopedia of Industrial Chemistry
Midified phenolic resin used for bond in abrasive products
As phenolic resin is as much as 80% as bond in abrasive products, at same time that
phenolic resin has some limitions, therefore modified phenolic resin is a very import
issue in bond of abrasive products research [11-13] [13] N. Reghunadhan: progress
in Polymer Science Vol.29 No.5 (2004), p.401 [14] B.H. Sun, J. Peng, W.J. Zou:
Chemical Engineer No.9(2009), p.04. Using nano powder for modifing phenolic
resin. Sun baoshuai [14]used nano SiO2 particles to modify phenolic resin. SiO2
particles is better bond with oxygen in materials, to improve the bondforces in
molecules. Jiang [15][15] W. Jiang, S. Chen,Y. Chen: J Appl ．Polym．Sci．Vol. 106
No.6(2006)，p.5336 research on different organisms to modify Monte-formaldehyde
resin and to make nanocomposites, it found that the nanocomposite thermal
resistance than pure phenolic resin high. Peng Jing etc [16] [16] J.Peng, et al:
Diamond & Abrasives Engineering No.1 (2007), p.49used preparation method to
produce nano SiO2/phenolic resin. Experimental studies has shown that abrasive

15
products that used it as bond has better impact strength, thermal stability, tensile
strength than the ordinary phenolic resin abrasive. To modify phenolic resin with
multiple carbon nanotubes, Wei huazhen et al[17][17] H.Z. Wei, Y.Li, C.M. Gao,
Z.H. An, S.L. Wang: Engineering Plastics Applications Vol.34 No.6 (2006), p.13,
Meng-Kao et al[18] [18] M.K. Yeh, N.H. Tai: Composites Part A Vol.39
No.4(2008), p.677. and Li

2.3 POLYIMIDE RESIN

Polyimide resins used in abrasive products. Polyimide resin was developed by
DuPont in the 1960s originally as a high-temperature lacquer for electrical
insulation. By the mid 1970s, it had been developed as a cross-linked resin for
grinding wheels giving far higher strength, thermal resistance, and lower elongation
than conventional phenolic bonds. The product was licensed to Universal Diamond
Products (Saint-Gobain Abrasives) and sold under the trade name of Univel, where
it came to dominate the high-production carbide grinding business especially for
flute grinding.
Polyimide has five to ten times the toughness of phenolic bonds and can
withstand temperatures of 300°C for 20 times longer. Its resilience also allows it to
maintain a corner radius at higher removal rates or for longer times than phenolic
resin (Figure 6.14).
Polyimide resin usually divided into two categories: one is the thermoplastic
polyimide resin, generally as insulation and heat insulation materials; the other is
the thermosetting polyimide resin, such as the PMR polyomides, acetylene-
terminated polyimide and Bismaleimide Oopolyiner Resin. Polyimide is more
expensive, low cost performance, so its application is limited. Peng jing [5] J. Peng:
Henan Chemical Indusrty Vol.25(2008),p.17.(from Henan university of technology)
made experimental research on three type polyimide resin, with the help of infrared
spectroscopy and differential thermal analysis, three polyimide resin were compared
and conclusions about mechanical properties, heat resistance, hardness etc had been
drawn and three polyamide resin applications (cutting, grinding, finishing) had been
summed up.. Zang jianyingJ.Y. Zang Jianying, et al: Diamond & Abrasive
Engineeting No.1(2005), p.42. adopted Epoxy Resin and Polyamidimide to produce
a resin bond. which is suitable for special-shaped diamond abrasive tool. In recent
year as polyimide resin performance continues to be improved, polyimide resin with
higher heat resistance is used to instead of the traditional resin in producing super-
hard abrasive products H. GLYNL: Industrial Diamond Review Vol49
No.532(1989),p.123. Polyimides are polymers, which contains a noncarbon atom of
nitrogen in one of the rings in the molecular chain. Phenolic bond has a less
toughness, less thermal resistance and less elasticity than polyamide and polyimide
resin. For instance: polyimide bonds have 5 to 10 times the toughness of phenolic
bonds and can stand temperatures of 300˚C for 20 times longer than phenolic bonds.
The of copper particles into the bond greatly improves the thermal conductivity.
Hollow glass spheres can also be used to give the wheel a degree of porosity. Since
resinoid bonds do not chemically attach to the abrasive grains, in many cases
‘rough’ or ‘spikey’ metallic coatings are applied to the grains to increase

16
mechanical retention in the bond. Rubber, shellac and silicate bonds are not
considered in this paper as they are rarely used for precision
https://doi.org/10.1016/S0007-8506(07)60031-6

RESIN BOND WHEELS

Resinoid wheels are susceptible to chemical attack by alkaline cutting fluids which
adversely affect their strength, especially with prolonged exposure at elevated
temperature. The fluid not only lowers the strength of the resin itself, but can
weaken its bonding to the abrasive, which is one reason why aluminum oxide grains

17
for resinoid wheels are specially treated with a thin coating. Grinding fluid attack
may not be a problem with heavy-duty and cut-off wheels, in so far as they are often
used dry. The strength of superabrasive resinoid wheels generally does not depend
on the resinoid bond, since it is only in a thin outer layer. However, alkaline
grinding fluids will likely degrade the wheel performance over a period of time
Malkin, S., & Guo, C. (2008). Grinding technology: theory and application of
machining with abrasives. Industrial Press Inc.
(file:///C:/Users/USER/Downloads/Grinding%20Technology%20-%20Theory
%20and%20Applications%20of%20Machining%20with%20Abrasives%20by
%20Malkin,%20Stephen%20Guo,%20Changsheng%20(z-lib.org).pdf)Resin covers
a broad range of organic bonds fabricated by hot pressing at relatively low
temperatures,and characterized by the soft nature of cutting action, low temperature
resistance, and structural compliance. The softest bonds may not even be pressed
but merely mixed in liquid form with abrasive and allowed to cure. Concepts of
grade and structure are very different to vitrified bonds. There is no interlocked
structure with bond bridges (because there is minimal porosity), but rather an
analogy would be to compare the grains to currants in a currant bun!

(RWTHedition) Barbara Linke (auth.) - Life Cycle and Sustainability

Spesification of the bond

18
FIGURE 6.13 Temperature/time properties of resins.
Resin bonds can be divided into three classes based on strength/temperature
resistance (Figure 6.13). These are plastic, phenolic resin, and polyimide resin.
LIQUID RESIN

Liquid resole phenolic resin is used as a wetting agent to uniformly coat the grain.
Table 13.13 lists various liquid resins. Figure 13.18 presents an approximate
relationship between liquid resin and the properties of the grinding wheel. The main
role of the wetting agent is that it helps dissolve the powdered resin and evenly coat
the surface of the individual grains. Liquid resole phenolic resins can affect the
degree of wetting during mixing, the strength after molding, the flow and the degree
of crosslink density at curing. A typical liquid phenolic resin for this application is
prepared using a base catalyst, and has a final viscosity range of 100–1,000 mPa s at
25C,resin content of typically 70% and free phenol content between 10% and 100%.
Figure 13.18 shows the relationship of viscosity and molecular weight of the resin
with the condition of the coated grain and the strength of the finished product. In the
case of a water soluble resole resin, the resin that is low viscosity and low molecular
weight generally gives a high strength product suitable for low density wheels, but
the coated grain has less flow and less stability in storage. Conversely, a resin that is
high viscosity and high molecular weight generally gives a coated grain with better
flow and better stability in storage. The strength of this product is low and is
suitable for cut-off wheels and depressed center grinding wheels. The liquid resins
that use furan-group solvent like furfural or furfuryl alcohol as solvent have low
moisture content and result in high strength grinding wheels. This resin system is
suitable for grinding wheels with high hardness. However, these solvents quickly
dissolve the powdered resin and the coated grain has less flow and less stability in
storage.

Table 13.13 Liquid resin product line for grinding wheel

19
 center Depressed
(mPa s/25C)Viscosity

contentResin

Cut-off

Diamond
Solvent

Coolant use

Heavy-duty
No. Resin type

LA Low MW water Water ~200 ~72 XX

soluble alkaline catalyst resin
LB Medium MW alkaline catalyst Water ~400 ~70 XX XX X
LC Medium MW amine catalyst Water ~200 ~69 X X XX
LD Medium MW alkaline catalyst Furan ~200 ~60 X XX X X
Furan group group
LE High MW alkaline catalyst Water ~400 ~70 XX XX
XX: strongly recommend; X: recommend
Source: Sumitomo Bakelite co., Ltd, Japan

3. POWDER RESIN
Powdered resin is used as the principal resin binder. Table 13.14 shows a listing of
powdered resins. Figure 13.19 shows an approximate relationship between
properties of resin and the resulting properties of the grinding wheel. Powdered
phenolic resin affects the degree of wetting during mixing, the strength after
molding, the flow and the degree of cross-link density at curing, and helps
determine abrasive properties, strength, and heat resistance. Commercial powdered
novolac phenolic resins are made in two steps. The first step is the preparation of
solid novolac resin using acid catalyst, and the second step involves the combining
of the solid novolac resin with hexamine. The performance of powdered phenolic
resin is roughly determined by the molecular weight, which directly influences
flow, hexamine content, and particle size (see Fig. 13.19). The wide range of
powdered phenolic resins available can produce an equally wide range of grinding
wheels and customer needs. For example, a resin that has high hexamine content
has high heat, and is suitable for making high density, heavy-duty grinding wheels.
A resin with low hexamine content has good cutting efficiency, which is caused by

20
accelerated wearing, and is suitable for making grinding wheels for precise
grinding. A resin that has low molecular weight, provides high water resistance, and
is suitable for making grinding wheels used with coolant water.a
Table 13.14 Powder resin product line for grinding wheel

Cut-off
(mm/125C)Flow

content Hexamine
Point (C)Melting

centerDepressed

Coolant use

Heavy-duty

Diamond
No. Resin type

PA Straight resin ~95 ~20 Low X XX X X

X X
PB Straight resin ~85 ~45 Low X X XX
PC Straight resin ~90 ~28 Medi X XX X
um X
PD Straight resin ~85 ~40 Medi X X X X
um-
High
PE Straight resin with HAP ~102 ~12 High XX X
technology X
PF Straight resin with HAP ~95 ~33 High XX
technology
PG NBR modified resin ~80 ~40 Low X XX
PH Phenoxy resin modified resin ~100 ~27 High X X X
XX: strongly recommend; X: recommend
Source: Sumitomo Bakelite co., Ltd, Japan

EPOXY OR URETHANE RESIN

Epoxy resin. It divided into glycidyl type epoxy resin, olefin epoxidation (new
epoxy resin). Epoxy resin has strong adhesive force, small shrinkage, good chemical
stability etc. but poor heat resistance, easy loss abrasive etc. Under the same

21
conditions, the abrasive wear of epoxy resin abrasive tool is 3-5 times higher than
that of phenolic resin tool, at the same time it is with higher price. Epoxy resin is
not widely used as bond of abrasive products. It is usually as bond to manufacture
fine-grained polishing wheel and other special abrasive tool. Y. Hua, Abrasives
Introductions [M], Standards Press of China, Beijina(2004). Yin Yuhang[9]9] Y.H.
Yin, P.R.China.Patent 101,200,053(2008), etc,invented a combination of epoxy
resin compound abrasive grinding tool, which epoxy resin is the mass ratio of 15-
78%, with low cost, good wear resistance, high strength, and long life. Sturiale, etc
A. Sturiale, A. Vazquez, A. Cisilino,et al: International Journal of Adhesion &
Adhesives , Vol.27(2007), p.156 improves the bond strength of epoxy-amine system
by aid of adding soluable phenolic resin, the best enhancement is the phenolic resin
content of 10-20%, a very effective way to improve the bonding strength is to
increase soluble phenolic resin in epoxy resin.The softest of resin bonded wheels
are epoxy or urethane wheels. [2]Zhengzhou university researcher Meichen Liu1,
Yingping Qi2, Yongfeng Shen2,Hua Li they are solved in problem of poor
compatibility of traditional resins, improve its adhesion, toughness, corrosion, heat
resistance, salt spray, and other properties of the coating, the epoxy resin and
polyurethane was modified with organic silicon. Two kinds of methods of physical
blending and graft copolymerization to synthesize epoxy resin modified with
organic silicon, and their heat resistance, adhesion, compatibility and toughness of
epoxy resin can be improved. Epoxy resin modified with organic silicon is
transparent and non-layered latex long-term placement. The corrosion resisting
coatings produced by epoxy resin modified with organic silicon have good heat
resistance and good chemical resistance. The synthetic process has the
characteristics of simple, reliable and little environmental pollution.
Copolymerization of polyurethane with amino silicone oil can greatly improve the
corrosion resistance to metal of polyurethane and improve its salt spray resistance.
Epoxy resin and polyurethane modified with organic silicon have good prospect in
the future.
Liu, M., Qi, Y., Shen, Y., & Li, H. (2018). Study on properties of epoxy resin and
polyurethane modified with organic silicon. J. Chem., 1, 200.[
http://purkh.com/index.php/tochem ]
OTHER BOND SYSTEMS
There are several older traditional bond systems used with conventional abrasives.
These include the following.
RUBBER
Rubber bonds introduced in the 1860s are still used extensively for regulating
wheels for centerless grinding and some reinforced grades for wet cutoff grinding.
Manufacturing is becoming an increasing problem for environmental reasons, and
alternatives, such as epoxy, are being substituted where possible. Rubber bonds
consist of vulcanized natural or synthetic rubber-rubber bonds are relatively cool-
grinding bonds, as the dulled grains can break off relatively easily and early,
limiting frictional heat transfer into the abrasive tool. Rubber bonds can also be
reinforced by fibers to reduce bond wear. A main cause for application of rubber
bonded abrasive tools is the mechanical compliance of these tools and therefore

22
flexibility in adaption onto the shape of the workpiece in polishing applications.
Menard, J. C., & Thibault, N. W. (2000). Abrasives. Ullmann's Encyclopedia of
Industrial Chemistry.
Natural or synthetic rubbers or combinations are milled between rolls to break
down the fibers, after which the abrasive grain, fillers, and sulfur for vulcanization
are added. After being mixed, the batch is calendered to the required thickness, cut
to shape, and heated to 150 – 175 C to vulcanize the rubber. Depending on the
amount of sulfur, type of rubber, and variety and amount of fillers, the product may
range from soft and resilient to hard. Because of strength and resiliency, rubber
cutoff wheels, particularly thin ones, give accurate cuts with good surface finish and
little burring in wet-grinding operations. Another application is the grinding of ball
bearing races and center less feed wheels.

SHELLAC
Shellac- or “elastic”-bonded wheels were first made in 1880, and, due to a
combination of elasticity and resilience, probably represent the best wheel for
producing fine, chatter-free finishes for grinding of steel rolls for the cold strip steel
mills and paper industries. Shellac comes from fluid exuded by insects onto
themselves as they swarm cassum or lac trees in India. As such, it is highly variable
both in availability and properties depending on the weather conditions and species.
On occasion, a single wheel maker can consume 10% of the entire world’s
production. Not surprisingly, many wheel makers have sought alternative solutions
to grinding applications. Menard, J. C., & Thibault, N. W. (2000).
Abrasives. Ullmann's Encyclopedia of Industrial Chemistry.
Shellac is a natural polymer prepared by heating and filtering the secretion of
the lac insect, a parasite found on tress in India and surrounding countries. A
common wheelmaking process involves coating the abrasive with shellac and hot
pressing the mixture in steel molds. The mix also may be calendered into thin
sheets, from which wheels are cut and cured at 150 – 175 C. Another method
involves moistening the abrasive with a shellac solvent, adding powdered shellac,
mixing, cold pressing, and postcuring. Shellac wheels exhibit a considerable degree
of thermoplasticity, giving rise to a soft grinding action with a distinct polishing
characteristic. They are used in some wet, light grinding operations, particularly for
fifinishing steel rolls.
SILICATE
Silicate bonds were first produced around 1870 by mixing wet soda of silicate
with abrasive, tamping in a mold, drying, and baking. It is still popular in certain
parts of the world by reason of its simplicity and low cost of manufacture. The
wheels are generally used for large face wheels. Silicate-bonded abrasives are
manufactured by mixing sodium silicate with abrasive and molding. The processing
temperatures are lower in comparison to vitrifified bonded wheels and processing
times are shorter. This is similar to magnesite bond whereby magnesite or burned

23
magnesium is combined with water to form Magnesium hydroxide producing a soft
grinding wheel which is used for finishing cutlery (Klocke 2009)Klocke F (2009)

THE ABRASIVE

CHARACTERISTIC OF ABRASIVE AND MATERIALS GROUND

Silicon carbide
The first abrasive to be synthesized abrasive was silicon carbide. There are two
main kinds of silicon carbide, characterized by their colour. Green silicon carbide
has higher purity and mainly used for accuracy grinding performances. Black
silicon carbide has higher toughness and used for rough grinding works. Silicon
carbide, also named as carborundum, is a combination of carbon and silicon with
the condensed formula SiC, composed of 70.045% silicon and 29.955%. Silicon
carbide has high mechanical strength, hardness, and ability to form as thick crystals,
which make SiC as a dominant abrasive material in abrasive tools. Also silicon
carbide has high thermal conductivity, high electrical conductivity, high
decomposition temperature and resistance to sudden temperature changes. For this
reason, it has found many applications in many variety of branches of industry.

Synthetic corundum
Synthetic corundum (Al2O3) can be produced in a Higgins arc furnace. It has high
resistant to the action of all kinds of acids and bases, both organic and inorganic. At
high temperatures (above 900˚C) synthetic corundum reacts with molten salts of
alkaline metals, producing aluminosilicates. Hydrogen can be corundum lowering
reason to suboxides of aluminum, although this happens only above 1400˚C. High
amount of carbon can be decrease Al2O3 at temperatures above 2000˚C. Synthetic
corundum is the most commonly used in abrasive tools. Abrasive property of
synthetic corundum is suitable for abrasive tools. But its abrasive ability belongs to
the quantity of additives. Except from the standard synthetic corundum, there has
other types such as:

White alumina: it has fewer impurities than standard synthetic corundum. The
major factor of this material is the potentiality of self-sharpening of the abrasive

24
grains during performance of the tool. Synthetic corundum grains have a bit lower
mechanical strength. This characteristic makes it advisable when especially accurate
performance is preferred and when the tool is to apply a low pressure on the
working area.
Modified synthetic corundums: these are materials based on aluminum oxide,
manufactured with the supplement of compounds that are able to become joined
into the corundum crystal lattice and form solid solutions with it. The most
commonly occurred modifiers are:
Chromium oxide (Cr2O3): Cr2O3 is a green fine-crystalline very hard material
used for polishing hard materials, such as chrome, platinum, and steel; the last one
acquiring a better corrosion resistancein the process.this modifier is used to generate
pink alumina, a material that has more quantity of crystals than white alumina,
better abrasive capacity, unchanged microhardness than white alumina.
Titania (TiO3): this modifier generate a material, has high abrasive ability and
more significant microhardness than white alumina.
Zirconia (ZrO2): this manufactures a material, contains high mechanical strength
and plasticity.
Monocorondum: this is a diversity of synthetic corundum, includes more valuable
grain isometry and smoother faces. It has higher microhardness and mechanical
strength than other variation of synthetic corundum. Also it has self-sharpening
ability.
Iron oxide
Fe2O3 is also known as jeweller’s rouge and varies in color from bright red to
violet; the darker the color, the higher the hardness. It is used for polishing metals,
glasses, and stones, and for very fine polishing of gold, silver, brass, and steel.Yang,
J. 1998. “The Change in Porosity during the Fabrication of Vitreous Bonded CBN
Tools.” K. KoreanCeram. Soc. 35, 9, 988–994.Richard. H Ser.No. 876,655 years
1972

GRAPHITE
Graphite is commercially available in various particle sizes and grades, both natural
and synthetic. The graphite should be less than 300 mircons numerical average par
ticle diameter and for best results, in the present invention the average particle size
of the graphite should be less than 50 microns, but should not be less than 1 micron.
Graphite, as commercially available varies in crystallinity. The more highly
crystalline the material is, the better it will perform in the present invention. Highly
crystalline graphite tends to be flaky in form, and the flaky shape is preferred.
Naturally occurring graphite comminuted to pass through a 325 mesh screen is flaky
in form and has been found very satisfactory in the present invention. Best results
were achieved with such a material having an aver age particle size (ignoring
thickness of the flakes) of 10 microns.Metal (nickel) coated graphite, as disclosed in
U.S. Pat, 3,402,035, may be employed in the present in vention, but no advantage
has been found in the present invention in having the nickel as a cladding on the
graphite as opposed to adding the nickel as an indpendent filler. S.Y.Luo1995
Graphite filler added to the resin bond have a positive influence on the grinding
performance of the wheel in dry grinding. Graphite filler has a positive influence an

25
abrasive retention because graphite filler act a as a lubricant to reduce friction if
decreases the thermal degradation of the resin bond.Luo, S. Y., Liao, Y. S., Chou,
C. C., & Chen, J. P. (1997). Analysis of the wear of a resin-bonded diamond wheel
in the grinding of tungsten carbide. Journal of Materials Processing
Technology, 69(1-3), 289-296.Graphite fillers added to the resin bond have a
possitive effect on the grinding performance of the wheel dry grinding.Gardner E.
Ser.No.523,523
LUBIRICANT
One method commonly used to alter the characteristics of a grinding wheel is by the
addition of fillers to the bond of the wheel. Fillers are added for many reasons.
There are inert fillers which reinforce the wheel but do not contribute to the
grinding performance. There are so-called active fillers which break down during
the grinding process and enhance cutting action. Fillers are sometimes added to act
as lubricants. Low-cost fillers may be added to decrease the cost of the wheel when
premium-priced ingredients are present. It is often difficult to select a filler or
combination of fillers which will contribute beneficially to more than one property
of a grinding wheel. For example:addition of one filler may contribute high
centrifugal and impact strength to a grinding wheel,but the metal removal rate drops
drastically. Conversely, a certain filler may produce a fast, cool cutting wheel, but a
wheel that is inadequate in strength. Various high-priced fillers may produce
effective wheels, but are economically out of reach of the consumer. The novel
combination of fillers according to this invention provides organic bonded grinding
wheels that have good grinding characteristics, extremely high tensile and impact
strength, and are economical to use. The novel combination of fillers according to
this invention provides organic bonded grinding wheels that have good grinding
characteristics, extremely high tensile and impact strength, and are economical to
use. Caserta et al.Appl. No.:131,778 1974 The present invention arises from the
observation that a unique material may be included with the mix ture of abrasive
and binder, which will replace part of the voids, and which will achieve a
lubricating action that will improve the cutting characteristics of the wheel and/or
extend the wheel life. JJ Guan, XF Xu and W Peng DOI:
10.1177/1350650114527071
Lubricants (like graphite, MoS2, WS2, MoSe2, nanoparticles, etc.) which possess a
laminar structure are usually applied as fillers in the development of polymer-based
self-lubricating materials. Thus, it is very interesting to investigate the friction
coefficient and abrasive wear mechanism of polymer-based composite materials
when the complexes are used as fillers.

26
Figure 11. The schematic model of the additive releasing and the lubrication layer
formation process.
Figure 11. It is summarized that the additives in the complexes are released in the
friction process, and form an abundant self-lubricating layer on the counter worn
surface under the interaction with the fragments of b-CD. The self-lubricating layer
has the functions of antifriction, anti-wear, and an improvement of surface quality.
The additives were released along with the decomposition of the complexes in the
friction process. The enhanced tribological properties of these abrasive tools were
attributed to the formation of a self-lubricating layer under the interaction of the
released additives and the fragments of bCD. The self-lubricating layer had
signifificant inflfluence on the process of resin transfer from substrate to the counter
steel surface and had functions of anti-friction, anti-wear, and an improvement of
surface quality. Jesse F. Ser. No. 383,926 1967
A purpose of the invention is to permanently retain in the pores of an abrasive tool,
such as a grinding wheel, a solid lubricant such as graphite, by introducing with, or
after, the introduction of the solid lubricant a resinous bonding material for retaining
the lubricant. A further, purpose is to impregnate an abrasive wheel such as an
abrasive grinding wheel, with a solid lubricant in a suitable medium, and to
introduce with, or after, the introduction of the solid lubricant, a resinous bond
which will hold the solid lubricant in the pores of the tool.
Typical of the most widely used of these solid lubricants is graphite. To some
extent, as later explained, the chlorinated napthalenes which are of waxy
consistency, such as tetra-, penta- and hexachloronaphthalene, possess the
properties of solid lubricants. Difficulty has been encountered with graphite in that
it is washed out of the pores of the wheel by the liquid coolants during service, and
therefore the effectiveness of the wheel is greatly reduced after a period of service.
Shaji, S., & Radhakrishnan, V. (2003). An investigation on solid lubricant moulded
grinding wheels. International Journal of Machine Tools and Manufacture, 43(9),
965-972.
Resin bonded wheels are manufactured in a similar manner to the vitrified wheels,
but the bonding medium is thermosetting synthetic resin and the baking temperature
is of the order of 150–200 °C only. These wheels.are soft structured and are used for
high speed grinding, rough grinding, cutting-off operations etc. The wheel wear rate
is high and the wheel softens when exposed to grinding fluids [13–16]. The low

27
baking temperature involved in resin bonding prompted the trials with solid.
Lubricants included in the wheel structure during molding. Such wheels with resin
bonding were successfully made and improved process results were obtained. But
the wheel wear depended on the type of the lubricant used. As an alternative way to
extract the advantages of solid lubricant application in grinding throughout the
usage of the wheel, solid lubricant molded resin wheels were developed with
graphite and CaF2 separately, by including solid lubricants during the molding stage
of the wheel. Trials to make such wheels with vitrified bonding failed due to higher
vitrifying temperature and non-availability of a good reduction furnace for firing.
The effectiveness of lubricants was evident from the improved process results
related to friction. The wheel wear depended on the type of the lubricant used. It
was higher with graphite and lower with CaF2. Saturation in lubricant effectiveness
could be observed on increase of the quantity of lubricant. Sioui et al. Appl. No.:
354,460
Solid lubricants useful in this invention include organic polymers such as polytetra
fluoroethylene, fluorinated ethylene polymers, chlorinated hydrocarbon, fluorinated
ethylene propylene, polyethylene styrene-butadiene, acrylonitrile butadiene-styrene,
polyurethane, polyformaldehyde, polycarbonate, and nylon and inorganic crystalline
solids such as boron nitride, tungsten disulfide, graphite, metal coated graphite,
molybdenum disulfide, niobium diselenide tungsten diselenide, and fluorinated
graphite. Köbnick, P., Velu, C., & McFarlane, D. (2020). Preparing for Industry 4.0:
digital business model innovation in the food and beverage industry. International
Journal of Mechatronics and Manufacturing Systems, 13(1), 334-335.
The lubricant properties are influenced by the following parameters:
1) Temperature
2) Pressure: The pressure at the tool–workpiece interface can reach very high
values especially in cutting operations where the lubricant has to be able to form a
limit lubrication layer in order to avoid direct contact between surfaces.
3) Shearstrength of the involved material surfaces.
4) Viscositythat has to be chosen according to the sliding velocity.
Lubricant is one or more substances (liquid or solid) interposed between tool and
workpiece in order to decrease their direct contact and so reducing both friction and
wear. Lubricants have to simultaneously fulfill various requirements. The most
important one are listed as follows [26]:
1) Constant low friction: The friction stresses should be low and uniform in order to
guarantee a homogenous deformation.
2) Separation of surfaces: The formation of a thin layer of lubricant avoids the
direct contact between tool and part surfaces so reducing friction and wear
mechanisms. Moreover, the lubricant film on the tool must be durable in order to
withstand continued or repeated contacts and separations with the workpiece
surface.

28
3) Thermal insulation: The lubricant should insulate tool and part in hot and heat‐
generating
processes so to reduce workpiece cooling and to protect the tools from excessive
heating.
4) Chemical inertness: The lubricant must not chemically interact with die, tool, and
work piece surfaces and with the surrounding atmosphere during part process or
storage. In fact, residues left on workpiece and tool should neither cause long‐time
changes in chemical or metallurgical properties (i.e. staining) nor interact during
following heat treatment. Moreover, the lubricant has to protect against oxidation or
gas absorption at high (furnaces or deformation induced) temperatures.
5) Rapid response: The lubricant must be effective in short times since the changes
involved in many manufacturing processes occur in few millisecond time lapses. In
other words, it has to rapidly respond to the process changes.
6) Controlled stability: The lubricant properties should remain stable. In particular,
it has to withstand against repeated encounters, oxidation, bacteriological attack,
and contamination, which are often present in industrial practice.
Moreover, the lubricant has to respect the following constrains:
1) Storage, application, and removal: Characteristics such as a long shelf life or
ease of controlled application and removal are all favorable.
2) Safe and disposable: The lubricant has to withstand the standards in force
regarding its environmental impact. At the end of its life, it should be completely
reclaimed and treated for reuse. Moreover, the effluents resulting from the treatment
must be environmentally acceptable.
3) Safety: Lubricants must not be toxic, carcinogenic, or cause irritation to skin.
Moreover, they should be odorless.
4) Cost: This factor becomes an important factor when the lubrication costs
(material and reconditioning for reuse and disposal) represent a significant portion
of the product total cost.

29
SUPER HARD ABRASIVE RESIN GRINDING WHEEL
Characteristics of super hard abrasive resin grinding wheel. Super hard abrasive
wheels are classified according to binders, mainly including the following
categories:
Table 1.2 Classification of superhard abrasive wheels In addition, high temperature
brazed single-layer superabrasive grinding wheel is being developed and applied in
China. Super hard abrasive resin grinding wheel uses diamond or CBN as abrasive,
resin powder as binder, and proper filling. The filling material is made by
compounding, mixing, hot pressing, curing, machining and other technological
processes, and has certain geometry shape, suitable for different grinding
requirements of processing tools.
[[Du, Z. J., Zhang, F. L., Xu, Q. S., Huang, Y. J., Li, M. C., Huang, H. P., ... &
Tang, H. Q. (2019). Selective laser sintering and grinding performance of resin
bond diamond grinding wheels with arrayed internal cooling holes. Ceramics
International, 45(16), 20873-20881.Resin bond diamond grinding wheels are
widely used in the precision grinding of hard and brittle materials such as glass,
ceramic, cemented carbide, sapphire, and semiconductor wafer. In resin bond
diamond grinding wheels, diamond grits are bonded by thermosetting resin (e.g.,
epoxy or phenolic resins) and different filler materials, providing reinforced bond
properties, inducing porosity and improving aesthetics. Both hard filler (e.g.,
aluminum oxide, silicon carbide, zirconia, and ceramic alpha alumina) and soft filler
(e.g., petroleum coke, pyrophyllite, lime, and graphite) have been used to reinforce
and control the breakdown rate of the grinding wheels [J. Hajduk, J.L. McArdle,
Resin Bonded Grinding Wheel, U.S. Patent, 2014 No. 14/ 0057534 A1.]]

30
Resin grinding wheel with superhard abrasive has grinding force and grinding heat
small, self sharpening, not easy to block, high machining efficiency, high surface
smoothness, very suitable for precision, ultra precision. Dense grinding and
polishing, at the same time, the production process is simple, the cycle is short, the
cost is low, and the performance is adjustable large proportion. However, due to its
low heat resistance, low bonding strength with inorganic materials and wear
resistance. Organic Abrasives have the disadvantages of poor heat resistance, low
bonding strength and fast wear. At present, the research of super hard abrasive resin
grinding wheel mainly focuses on the selection of new high temperature resistant
resin binder, abrasive and improvement of bonding strength between resin matrix,
development of resin grinding wheel with strong heat dissipation and high wear
resistance, resin super hard abrasive sand the grinding characteristics of the wheel,
as well as shaping and sharpening. Resin binder with high temperature resistance,
good adhesion and good process ability should be selected for resin grinding wheel
with superhard abrasive phenolic resin and its modified new varieties, such as
epoxy, polyvinyl chloride, polyamide and polyvinyl alcohol, are used Acetal,
bismaleimide and other modified phenolic resin also more use of heat resistance,
mechanical properties of higher polypheny lEther resin (known as Xylok resin in
foreign countries, such as Xylok 939p of British advanced resin products company)
is specially used for diamond and diamond In recent years, many scholars have
studied the use of photosensitive resin as a super absorbent The bond h7l of hard
abrasive wheel was developed by Peng Wei, Zhejiang University of technology, etc.
The silicon wafer is cut in a narrow slot. In order to improve the mechanical and
grinding properties of superabrasive resin grinding wheels, fillers are often added
White corundum powder, silicon carbide powder, graphite, carbon black,
molybdenum disulfide, chromium trioxide, iron oxide, zinc oxide Cryolite has been
studied by many scholars at home and abroad. For example S.Y.Luo and others
studied the addition of copper powder, silicon carbide and carbon black When dry
grinding cemented carbide with resin diamond wheel and other inorganic fillers, it
is found that copper powder can make the exposed condition of abrasive grains
better and increase with the increase of grinding efficiency, silicon carbide can
increase the wear resistance, and carbon black can improve the grinding effect.
Another example is the Russian patent (2083597) High speed heavy load grinding
wheel was prepared by cold pressing or hot pressing with cryolite silica as filler The
waste resin due of industrial cryolite production is mainly composed of sodium
fluoaluminate cryolite and silica The mixture of amorphous (Si02) is homogeneous
and evenly distributed, so it can not be prepared by mechanical mixing.
The heat dissipation effect of resin grinding wheel with superhard abrasive is
poor, and the resin is easy to carbonize and decompose under the action of grinding
high heat, which affects the resin As a result, a large number of abrasive particles
have fallen off (about 40-60%) before the grinding effect is fully exerted, which is
reduced.

31
DIAMOND (NATURAL AND SYNTHESISED)
In the history, diamond dust had been used to polish gems, and natural diamond had
been used to true grinding wheels, began to appear in the 1930’s. Natural diamond
wheels’ sales expanded outstandingly during the 1940’s, constituting 20 % of all
trading (by value) of the Norton Company by 1952. The first synthesis of unnatural
(artificial) diamond was reported by Bundy and his coworkers at General Electric in
1955.

Figure 1.1 Classification of diamond tools.

Figure 1.6 Resin-bonded tools. (Courtesy of EHWA Diamond Ind. Co., Ltd.)

Konstanty, J. (2011). Powder metallurgy diamond tools. Elsevier.

Synthetic diamond
Diamond is considered as superhard abrasive material. Diamond is one of the
allotropic type of carbon. Moreover it is the hardest mineral found on Earth (with a
hardness of 10 on the Mohs scale). Since the quantity of mined diamond is

32
inadequate to meet provide, leading to expensive cost, it has proved required to
prosper a method for synthesizing diamond. This was succeeded by the Swedish
company ASEA, 1953. After this success annual manufacturing of artificial
diamond has been unstoppably expanding. Diamond has density of 3.5g/cm3. Its
crystal lattice has the form of a cube including 18 carbon atoms. These carbon
atoms in the diamond are combined by high-energy covalent bonds, allow the
material its extraordinary hardness. On the other side, it has a good thermal
conductivity, makes heat to be removed efficiently during the grinding process.
Furthermore it has a small thermal expansion coefficient, minimizes thermal
deformation of tools with diamond grains. Another very fundamental characteristics
are anisotrophy of hardness and grindability. The material is resistant to the
influence of very strong acids and their mixtures. But it is dissolved in molten
hydroxides and salts such as NaNO3 and KNO3. Also it dissolves in molten iron,
above a temperature of approximately 800˚C. In the presence of air, it burns at a
temperature from 850˚C to 1000˚C. Synthetic diamond have other factors that differ
them from natural diamonds. They are usually smaller (with an average size
between 0.2-0.4mm) and have a dissimilar grain formation and a rougher surface.
Crystal vertices with smaller angles, smaller radii of curvature and surface
roughness makes synthetic diamond advantageous for abrasive machining.
Moreover amount of impurities in synthetic diamond is higher than in natural
diamonds. Procedure for synthesizing diamond are generate at high pressures
(reaching 10GPa) and high temperatures (up to 3000˚C).

Figure.2
Super grains, like diamond and cubic boron nitride (CBN), are superior to general
grains in hardness. Hardness differences as a function of temperature for diamond
and cubic boron nitride is shown in Figure 3. Diamond has lower heat resistance,
and its stable temperature of hardness is around 600˚C.
7. Kuniasi Unno (2007) Kensakukakou No Kiso. Nikkan Kogyo Shimbun pp
64–76

Polishing abrasives

33
Polishing abrasives may be required to be hard or soft according to the desired
material removal rates. Hard abrasives are employed for rough abrasive paste
compositions; examples are pumice, beryllium oxide (BeO), chrome oxide, Fe2O3,
garnet, corundum, emery, quartz, silica carbide, and glass. Soft abrasives are
employed for fine polishing paste compositions; examples include kaolin, chalk,
barite, talc, Tripoli, and Vienna lime. Pumice, Garnet, Emery, Quartz, Silica
carbide, Glass
Cubic boron nitride
Cubic boron nitride (borazon) is a member of superhard abrasive materials as a
diamond is proved by Robert H, Wentorf, became the first synthesize cubic boron
nitride successfully in 1957. Its crystal lattice is linked closely to the structure of
artificial diamond. Four are boron atoms of 18 atoms contained in a cube, and the
remainder nitrogen. Unlike diamond, in which all bonds are covalent, in cubic
boron nitride 75% are covalent bonds and other 25% ionic.[1] abrasive and abrasive
tool CBN abrasive grains, bond, pore builders and other additives are mixed at a
defined ratio and then pressed into a green body by a moulding process. The curing
or calcinations of a vitreous bonded cBN element can be performed by applying a
cold pressing process or a hot pressing process. In the cold pressing process, the
cBN element is cured within several hours at a temperature range between 700 and
950 °C with no additional pressure [20] [20] Kubota, O., Furukawa, H., Kiskimoto,
M., Ukai, N., 2006. Vitrified grinding wheel andmethod of manufacturing the same.
European Patent 1634678 A4. At hot pressing, the process takes only several
minutes under the pressure of up to 150 MPa within a temperature range between
700 and 950 °C [21]. Organic/synthetic resin bonded cBN green body elements are
commonly cured in a hot press mould for 30 to 120 minutes, at a temperature of at
least 150 °C and a pressure between 35 and 105 MPa [9] [9] Davis, J.R., 1995.
ASM Specialty Handbook Tool Materials, ASM International, Materials Park,
Ohio, USA. The metallic sintered bonded cBN elements can be produced similarly
to the hot or cold pressed vitreous cBN elements. The cBN green body element is
cured within 15 to 60 minutes, at temperatures between 600 °C and higher than
1,100 °C and a pressure between 14 and 140 MPa Davis, J.R., 1995. ASM Specialty
Handbook Tool Materials, ASM International, Materials Park, Ohio, USA. A full
body cBN grinding wheel or a wheel hub coated with a cBN layer or segments can
be produced depending on the grinding wheel design, size and working speed
requirements. The full body cBN grinding wheels are mostly common for small
grinding wheels and low grinding wheel speed, as used in an internal grinding
process. With increasing grinding wheel size and grinding wheel speed, a cBN
layer/ring or cBN segments are coated on a wheel hub. The wheel hub materials are
commonly composed of low alloyed steel, aluminium, bronze, ceramic or synthetic
resin (fibre-reinforced; with metallic or non-metallic fillers) Klocke, F., Konig, W.,
2005. Fertigungsverfahren II -Schleifen, Honen, Lappen (Manufacturing processes
2-Grinding, honing, lapping). Springer-Verlag Berlin Heidelberg, Germany (in
German). The selection of the wheel hub material depends on the requirements of
the grinding process regarding the maximal burst resistance value and grinding
wheel speed. The burst resistance is tested, as a final process step, to make sure that
the grinding wheel meets the defined specifications.

34
Diamond and cubic boron nitride (CBN) wheels, which are complementary to each
other on adaptability, are generally called superabrasive grinding wheels. Grinding
with superabrasive wheels o;ers a series of advantages such as long wheel life, high
grinding eBciency, surface quality, and dimensional stability. Diamond wheels are
applicable to grinding of hard and brittle non-ferrous metals, horniness alloys and
hard and brittle non-metals like optical glasses, ceramics and gems while CBN
wheels are to grinding of ultra hard and tough metals like chilled steels and thermal
durable alloys. Due to their superior grinding performances, they are extensively
applied to such Celds as aerospace, automobile, medicine, electronics and building
materials, meanwhile they are what precision and super-precision grinding, high
speed and eBciency grinding, hard-to-machine materials grinding, proCle grinding
and grinding automation are based on.Xie, X. Z., Chen, G. Y., & Li, L. J. (2004).
Dressing of resin-bonded superabrasive grinding wheels by means of acousto-optic
Q-switched pulsed Nd: YAG laser. Optics & Laser Technology, 36(5), 409-419.
https://sci-hub.tw/https://doi.org/10.1016/j.optlastec.2003.11.002

http://dx.doi.org/10.1016/B978-1-4377-3467-6.00001-X Marinescu, I. D., Rowe,

W. B., Dimitrov, B., & Inaski, I. (2004). Tribology of abrasive machining
processes. Elsevier.
Grinding with superabrasive wheels offer a series of advantages such as long wheel
life, high grinding efficiency, fine surface quality, and fine dimensional stability.
Diamond wheels are applicable to grinding of hard and brittle non-ferrous metals,
horniness alloys and hard and brittle non-metals like optical glasses, ceramics and
gems while CBN wheels are to grinding of ultra hard and tough metals like chilled
steels and thermal durable alloys.(Li, S. L., Lin, T., Wang, Z., & He, X. B. (2014).
Effect on the grinding performance by the different elements of the auxiliary
material. In Advanced Materials Research (Vol. 893, pp. 649-652). Trans Tech
Publications Ltd.) Due to their superior grinding performances, they are extensively
applied to such fields as aerospace, automobile, medicine, electronics and building
materials, meanwhile they are what precision and super-precision grinding, high
speed and efficiency grinding, hard-to-machine materials grinding, profile grinding
and grinding automation are based on Because the super-hard material is very
expensive, it is necessary to save super-hard materials and give full play to their
utility. Considering the good wear resistance and long using period of the diamond,
the work layer with diamond is often made into a thin layer and beset on the non-
work layer. Therefore, the diamond abrasive tool usually consists of three parts: the
substrate, the transition layer and the work layer. The manufacturing of resin-
bonded diamond abrasive tool is similar to that of ordinary resin-bonded abrasive
tool, but the formula and the process operation are somewhat different. The formula
features of resin-bonded diamond abrasive tool are more filler and less abrasive, and

35
the process feature is hot press molding. The typical manufacturing process flow of
resin-bonded diamond abrasive tool is shown as fig.1.

Fig.1The typical manufacturing process flow of resin-bonded diamond abrasive tool

(Liu, N. B., Wu, Z. Y., Li, G. Y., & Weng, N. (2011). Research on the CAD
Technology of Resin-Bonded Diamond Abrasive Tool Based on Quality Control.
In Key Engineering Materials (Vol. 487, pp. 204-208). Trans Tech Publications
Ltd.)
The Analysis of Quality Influencing Factors of Resin-bonded Diamond
Abrasive Tool
It is studied that the quality of resin-bonded diamond abrasive tool mainly depends
on the following two design links:
①The formula design of abrasive tool. The formula is the reflection of types and
numbers of raw materials. It is an important basis for preparing molding materials in
the production. The contents of formula generally include the type and size of
abrasive grain, the type and dosage of adhesive, the type and dosage of filler, the
concentration, the molding density, etc. Among them, the factors significantly
influencing the quality of abrasive tool include the dosage of adhesive and the
molding density. The dosage of adhesive is one of the main factors influencing the
hardness. Increasing the dosage can improve the hardness and strength of abrasive
tool. While under the condition of the same type and size of abrasive grain as well
as the same dosage of adhesive, with molding density increasing, the hardness and
strength of abrasive tool also increase.
②The manufacturing process flow design. The manufacturing process of resin-
bonded diamond abrasive tool generally includes confecting, mixing, molding,
curing. In the above processes, the factors significantly influencing the quality of
abrasive tool include the mixing time in the process of confecting and mixing, the
molding pressure and compression speed in the process of molding, the highest
curing temperature and heating rate in the process of curing. In the above two
design links, the selection and setting of different parameters has different influence
on the quality of resin-bonded diamond abrasive tool. Therefore, the essence of
controlling the quality of resin-bonded diamond abrasive tool is to control the
corresponding parameters in the design links. In the abrasive tool CAD technology
based on quality control, starting with the formula design and the manufacturing
process flow design, expected goal can be achieved by controlling parameter
selection method and parameter setting strategy. (Liu, N. B., Wu, Z. Y., Li, G. Y., &

36
Weng, N. (2011). Research on the CAD Technology of Resin-Bonded Diamond
Abrasive Tool Based on Quality Control. In Key Engineering Materials (Vol. 487,
pp. 204-208). Trans Tech Publications Ltd.)
Comporation of crystal Structure

Superabrasives, Table 1 Physical properties of abrasive materials (Klocke 2009;

Toenshoff and Denkena 2013; Rowe 2009)

Superabrasives, Fig. 1 Structure of diamond (Bailey and Juchem 1998)

Superabrasives, Fig. 2 Structure of CBN (Bailey and Juchem 1998)

37
FILLERS IN RESIN BONDS
[Du, Z. J., Zhang, F. L., Xu, Q. S., Huang, Y. J., Li, M. C., Huang, H. P., ... & Tang,
H. Q. (2019). Selective laser sintering and grinding performance of resin bond
diamond grinding wheels with arrayed internal cooling holes. Ceramics
International, 45(16), 20873-20881. The filler ma
terials such as oxides (e.g., CaO and MgO), pyrite (FeS2), cryolite (Na3AlF6), zinc
sulfide (ZnS), lithopone (ZnSBaSO4), potassium fluoroborate (KBF4) and
potassium aluminum fluoride (KAlF4 and K3AlF6), potassium sulfate (K2SO4),
and mixtures of these materials are often introduced to improve the grinding
performance [2]. Moreover, metal powders such as Cu and Ni have been used as
filler to increase the thermal conductivity and strength [3]

Fillers in resin bond have several duties in producing level and grinding
performance. Cryolite-(Na3AlF6), Pyrite-(FeS2), Zinc sulfide-(ZnS), lithopone -
(ZnSBaSO4), potassium fluoroborate and potassium chloride-(KAlF 4, K3AlF6),

38
potassium sulphate- (K2SO4), and mixtures of these materials (KCl) are well-known
fillers in resin bonded grinding tools.
Colleselli K, Schwieger KH (1988) Schleifscheiben und Schleifko ¨rper. In:
Becker/Braun (ed) Kunststoff-Handbuch 10-Duroplaste. Hanser Verlag, Munich, pp
894–908. ISBN 978-3-446-14418-7
10. Gardziella A, Pilato L, Knop A (2000) Phenolic resins: chemistry,
applications, standardization, safety, and ecology, 2nd edn. Springer, New York
21. Hickory GE, White MJ (1991) Patent US 5,061,295—Grinding wheel abrasive
composition
The toxic materials antimony trisulfide (Sb2S3) and lead chloride (PbCl2) were used
back in the day, but are substituted by special iron halides and others. Basic oxides
such as CaO and MgO fillers can speed up the hardening procedure. Nevertheless,
CaO fillers are able to hydrate and move into CaCO3 in contact with cooling
lubricant so CaO should only be applied to grinding tools for dry grinding. Fillers
fortify the bonding in toughness, strength, heat resistance and burst resistance in the
grinding phase. Fillers can change the tools’ outer look when they act as coloring.

Filler in performance of resin bonds

Resin bonds for abrasive tools consist of single resins or a resin combination with or
without fillers. The resin itself is produced by esterification or soaping of organic
compounds. Filler materials can increase toughness, heat resistance, breakage safety
and strength. Moreover it reinforce the grinding procedure as secondary abrasive.
Dulfides, silicates, halogenides are possible to expand the bonding strength and
wear resistance and bother the oxidative degradation of resin.
Resin bonds have high flexibility. But resin bonds are extra sensitive to heat. They
degrades at temperature above 200˚C and grit coatings assist to dissipate the
grinding heat. Resin bonded wheels have restricted shelf lifetime and must be used
within two years. The polycondensation performance, which hardens the bond
resins does not make proper hardening so that the strength of resin bonds can
change because of atmospheric or chemical exposure. Abrasive articles consist of:
abrasive (e.g., fused alumina), wetting agent (e.g., resol), binder (e.g., novolak), and
filler (e.g., pyrite–FeS2, cryolite–Na3AlF6). The first stage during production of
abrasive articles involves wetting of the abrasive by the wetting agent. Then, the
binder mixed with fillers is added. Fillers in resin bonds have several tasks in both
manufacturing phase and grinding operation: They induce porosity, reinforce bond
properties, change aesthetics, and more. Common fillers in resin bonded grinding
tools are cryolite (Na3AlF6), pyrite (FeS2), zinc sulfide (ZnS), lithopone
(ZnSBaSO4), potassium fluoroborate and potassium chloride (KAlF4, K3AlF6),
potassium sulphate (K2SO4), and mixtures of these materials (KCl) . The toxic
materials antimony trisulfide (Sb2S3) and lead chloride (PbCl2) were used in the
past, but are substituted by special iron halides and others. The percentage of fillers
and resin bond varies with the grinding tool hardness and density (Table 3.1). In the
manufacturing phase, fillers can induce porosity. Basic oxides, such as CaO and
MgO, are fillers that accelerate the hardening process. However, CaO should only
be applied to grinding tools for dry grinding operations, because CaO fillers can
hydrate and transform into CaCO3 in contact with cooling lubricant. In the grinding
process, fillers reinforce the bonding in toughness, heat resistance, strength, and
burst resistance or they support the grinding process as secondary abrasive. Glass
chips reinforce wheels around the inner diameter. Fine metal powder of high
thermal conductivity can be introduced into the bond to improve the tool’s heat

39
absorption in the machining process. An example is fine silver powder, mesh size
325 or finer . In addition, fine silicon carbide grits act as bond strengtheners.
Also filler is divided into active and inactive fillers. Active fillers are: litopone,
pyrite, silica, potassium cryolite, cryolite and potassium fluroborate. Inactive fillers
are: glass fibers, copper slag, soot, inorganic oxides (Fe2O3, ZnO, Al2O3 etc), and
some natural polymers.

ACTIVE FILLERS
Gardner E. Ser.No.523,523
The novel combination of fillers according to this invention provides organic
bonded grinding wheels that have good grinding characteristics, extremely high
tensile and impact strength, and are economical to use. The novel combination of
fillers according to this invention provides organic bonded grinding wheels that
have good grinding characteristics, extremely high tensile and impact strength, and
are economical to use. the invention are set forth in the appended claims; the
invention itself, however, both as to its organization and method of operation,
together with additional objects and advantages thereof, will best be understood
from the following description of a specific embodiment. It has long been known
that chemical compounds which contain sulphur or halogens such as chlorine and
fluorine, among others, are advantageous as fillers in grinding wheels. Many of
these compounds break down during grinding with the evolution of volatile
grinding aids at the point of grinding contact. These fillers are known as active
fillers or grinding aids. It has also been known that such decomposing fillers tend to
weaken the bond of the grinding wheel. This is not an entirely detrimental effect
because the bond must break down to release the dulled and worn abrasive particles.
However, the optimum amount of decomposing filler must be carefully calculated
to provide a bond which will break down fast enough to expose fresh abrasive
particles when needed, and yet not so fast that it will release the abrasive grits pre
maturely. Another problem to be faced in the formulation of grinding wheels is the
provision of a wheel with adequate strength against centrifugal force and impact.
Various types of strengthening elements such as glass, asbestos and mineral fibers
are often used. Such strengthening mediums are compatible with organic bonding
materials, but are completely inert and often impede grinding action. Where metal
particles have been used in quantities suffi cient to strengthen grinding wheels it has
been found that the cutting action of the wheels is greatly impaired. It appears that
these particles prevent the bond from being broken down to release dulled and worn
abrasive particles. It is for this reason that metal particles do not find general use as
reinforcing mediums for grinding wheels. Where, however, an active filler and a
strengthening metal medium are judicially selected to co-react as taught herein, the
metal particle is reacted at the precise moment when its holding strength quality is
no longer desired. At the same time, as taught herein, the metal reacts with the
active filler to release considerably more grinding aids in the form of decomposition
products of the active filler. The overall effect is an extremely strong grinding wheel
with improved grinding performance due to in creased amounts of grinding aids for
a given quantity of active filler. A typical filler combination embodying the

40
invention comprises a metal powder and a metallic salt. The ductility of the metal
powder gives improved impact strength to the bond, and this powder is selected to
enter into a chemical reaction with the metallic salt during grinding to provide
controlled thermal breakdown. In addition, the reaction is accompanied by the
evolution of volatiles which have a beneficial effect on the grinding action. ve
grains, a filler combination for said bond com prising at least a reinforcing material
and an active filler which upon the application of heat co-react exothermical ly to
produce a grinding aid composition, the reinforcing material consists essentially of a
metal selected from the group consisting of aluminum, zinc, magnesium, cadmium
and copper and said active filler is selected from the groups consisting of halides or
sulphides of iron, lead, tin and cadmium. An abrasive article as described in claim
wherein said reinforcing material and said active filler are aluminum and iron
pyrites respectively. An abrasive article as described in wherein the reinforcing
medium comprises 5-35% by volume of the bond and the active filler comprises 5-
30% by volume of the bond. An abrasive article as described in claim 6 wherein the
active filler is a blend of coarse and fine grit. Caserta et al.Appl. No.: 131,778 1974
IN ORGANIC FILLER
The polymeric binders can also contain many inorganic fillers known in the art such
as cryolite (NasAlFs), lime (CaO), iron pyrites (FeS2), potassium fluoroborate
(KBF), potassium aluminum fluoride (KAlFs), common salt (NaCl), sodium
sulfate(Na2SO4), potassium sulfate (K2SO4), zinc sulfate (ZnSO), stibnite (SbS)
and zinc sulfide (ZnS). It is generally known that an abrasive-binder formu lation
may be pressed to a desired porosity. As the wheeel is pressed to a lower porosity, it
becomes harder whichusually results in a longer life fo for the abrasive product.
Unfortunately, the metal removal rate usually drops with increasing wheel hardness.
Siqui et al. Appl. No.: 163,976 RESEN-BONDED ABRASIVE TOOLS WITH
METAL FILLERS
High ratios of metal removed to abrasive tool wear are achieved when resin-bonded
diamond or cubic boron nitride abrasive tools include in the bond from 10 to 60
percent by volume of silver, silver coated copper, or copper powder in the presence
of from 5 to 30 per cent by volume of a solid lubricant. Other fillers such as finely
divided metal oxides or carbide such as sili con carbide may be present in an
amount of from 0 to 40 percent by volume, depending upon the total con tent of
metal and lubricant. The diamond wheels or tools of this invention are particularly
suitable for the dry grinding of carbide tools. The cubic boron nitride wheels
employ metal clad boron nitride abrasive particles and are particularly suitable for
the dry grinding of hard steel tools, that is, high speed steels such as T15, M2, M3,
and M4. Solid lubricants useful in this invention include organic polymers such as
polytetra fluoroethylene, fluorinated ethylene polymers, chlori nated hydrocarbon,
fluorinated ethylene propylene polyethylene styrene-butadiene, acrylonitrile
butadiene-styrene, polyurethane, polyforaldehyde, polycarbonate, and nylon and
inorganic crystalline solids such as boron nitride, tungsten disulfide, graphite, metal
coated graphite, molybdenum disulfide, niobium diselenide tungsten diselenide, and
fluorinated graphite. For the production of coated abrasive discs or belts, a liquid
phenol-formaldehyde resin can be used. A size coat of liquid resin should be

41
employed after the maker coat, and at least the size coat should contain the fillers of
this invention. The size should be “high," that is, it should extend from the maker
coat to close to the tips of the abrasive so that the fillers in the coat contact the work
during grinding Thompson. Appl. No. 429,996. 1975
Metal filler here exists a class of grinding wheels called metal filled organic bonded
grinding wheels. This class of grinding wheels comprise abrasive grit, an organic
resin bonding material such as the phenols, epoxies, polyi mides, shellac and others,
into which a mctal filler has been uniformly distributed. The metal filler may be
added to make the grinding wheel electrically and thermally conductive in which
case copper, aluminum mixtures or alloys thereof are used as fillers. These metals
and together with iron and other metals are also used to strengthen the bond. They
are chemically inert with regard to the bonding material. The metal filler acts as
reinforcement. Instead of a pure resin matrix surrounding the abrasive grit and
forming posts which reach from abrasive grain to abrasive grain holding them
together, a metal resin composite matrix performs this function in metal filled
abrasives. Sce the figure in the Ball U.S. Pat. No. 2, 162,60().Harris et al. Appl. No.:
688,532 Filler
An extensive list of fillers, i.e. materials added to the organic polymer bond, have
been utilized at one time or another in bonded abrasive products. Of this large list
only a relative few are widely used on a commercial basis viz. sodium chloride, iron
sulfide, potassium fluor- borate, sodium fluoraluminate, tin powder, fine alumi num
oxide, fine silicon carbide, graphite, calcium carbonate, and various combinations
thereof. Generally, fillers are not added to the polymeric bond in grinding wheels
for the sake of extending or diluting the poly- mer, as is commonly done in other
polymer based articles of manufacture. Fillers are employed in abrasive products
most often for their beneficial effect on the grinding characteristics of the abrasive
product, and sometimes as a reinforcing agent. Calcium oxide is an- other material
added to polymeric bonds. This material is generally not considered a filler; it is
added to the bonds of the harder or denser types of phenol-formalde hyde resin
bonded abrasive products for the purpose of scavenging water generated during the
curing process of such abrasive product types. Bonded abrasive products are
manufactured predom inantly by two distinct methods. Softer grade products, i.e.
those containing a significant amount of porosity, are made by the cold-pressing
method. Abrasive grain is wetted with a pick-up agent; a powdered prebatched bond
made up of a thermosettable polymer and filler if desired, is then added to the
wetted abrasive and the combination mixed until all or most of the powdered bond
is picked up by the wetted abrasive; a predeter- mined quantity of this mix is placed
in an appropriately shaped mold and spread uniformly therein; the mold is
assembled and the mix pressed at room temperature to the desired density; the green
wheel is then removed from the mold and subjected to a heat treatment to advance
or cure the polymeric bond. The other manufacturing method is the so called hot-
pressing method. This method is essentially the same as the cold-pressing method
described above, up to the point of the actual pressing. Instead of applying pressure
at room temperature, the mold set-up and mix contained therein are heated e.g. to
160° C. while the pressure is being applied. This method is used to manu facture
wheels which are essentially free of pores. Products made in this manner are

42
commonly referred to as zero porosity. However, some of these products do contain
as much as 5% porosity. Both of the foregoing processes are well known and
widely, if not almost exclusively, used for the commercial production of bonded
abrasive products. The two-stage resin composition which produced a wheel closest
to a shellac wheel was that containing 0.77% hexa, when an amount of liquid one-
stage phenol-formaldehyde resin equal to about 15% of the combined weights of the
liquid one-stage resin and the powdered two-stage resin. If the amount of liquid
one-stage resin is increased or decreased, then the optimum hexa
methylenetetramine level will increase or decrease within the prescribed limits of
0.5 to 2.5% by weight of the two-stage resin.t shouldalso be understood, that the
effect of bake or cure cycle variations and filler additions to the bond, are within the
scope of the instant invention. It is well known, for example, that low temperature
bake cycles applied to phenol-formaldehyde bonded abrasive products result in a
relatively undercured bond and a wheel which is softer acting in its grinding
characteristics. The addition of fillers to the bond can be used to harden or soften
the grinding action, or to improve the grinding efficiency, depending on the
particular choice of filler or fillers.

Common fillers for super-hard resin abrasives

Filler is an important ingredient in super-hard material resin abrasive, its duty is not
only used to enlarge the heat resistance, hardness, strength of the bond but also
durability of the grinding wheel. There has many types of fillers. In China Cr2O3,
ZnO and Cu powder are mainly used for diamond resin abrasives and phenolic resin
binders.
Polyimide binders are used for dry grinding without Cu powder. Zr, Co, CaCO 3 etc
are can be added for wet grinding, ceramic materials such as quartz powder (SiO 2),
aluminum oxide powder (Al2O3) can be added.
The filler in the binder is normally metal powder, metal oxide powder such as Cu,
Cr2O3 etc for cubic boron nitride resin abrasives. The usage of TL (GC) and GB
(WA) abrasives as filler for dry grinding is preferable, but it is not suitable for CBN
recovery.
The fillers used abroad are electroplated MoS 2, some metal salts, such as BaSO 4,
MgSO4. The quantity of abrasive has a remarkable effect on the grinding effect,
mostly to increase the grinding performance and mechanical characteristics of the
abrasive. Also fillers are can be a part in filling the unit volume. As the filler, metal
powder can increase the hardness and strength of the grinding tool, which is
effective and convenient to the conduction and diffusion of grinding heat. But too
much filling will lead to fall off the abrasive bond, and the abrasive is not simple to
come out of the blade. In serious situation, it can cause blockage, fire the workarea,
the diamond on the surface of the abrasive tool burns, and consumption will
enlarge.
Additionally, for improving the grinding performance and mechanical performance
of the grinding tool, some solid lubricant materials can also be added suitably,
mainly dry grinding. Its main duty is decreasing the friction. Too much filler will
minimize the strength of the abrasive.
The properties and performances of several fillers are shortly written below:
1. Cu powder
Cu has a high melting point (1083˚C) and good thermal conductivity. High
temperature generated during the grinding procedure can be rapidly transferred to

43
the base of the grinding tool through Cu, the heat is speedily dissipated. There by,
decreasing the overheating phenomenon in the grinding area and raising the heat
resistance of the bonding agent. Cu and resin are chemically absorbed. It has good
adhesion and wear resistance. Its coefficient of thermal expansion is close to the
polyimide. These characteristics are beneficial for increasing the wear resistance of
the grinding wheel. The shelf lifetime of the grinding wheel expands when using Cu
powder compared to the without Cu powder. Even Cu is a flexible material with
high ductility and excessive dosage. The grinding ability is decreased and grinding
wheel is easily stuffed. Typically add 15%-20% Cu powder (or mixed with graphite
powder) is used as a filler for the production of electrolytic grinding wheels.
Electrolytic grinding can increase the work efficiency and reduce the processing
time. For higher roughness workpieces coarser-grained grinding wheels are suitable.
2. Cr2O3 and ZnO
Cr2O3 is a dark green hexagonal crystal with a density of 5.1-5.2g/cm 3, melting
point of 2435˚C. ZnO is white hexagonal crystal or powder density 5.6g/cm 3,
melting point 1975˚C amphoteric compound. These metal oxides have a higher
melting point and mechanical properties, can definitely expand the strength,
hardness and heat resistance of the grinding wheel. But Cr2O3 is hardener then ZnO
sand and lower abrasion ratio. However, their effects are very similar and are often
mixed together. Normally, Cr2O3: ZnO=1;1-2.1. The fromer is used for external an
internal grinding, sharpening, the latter is used for dry grinding and fine polishing.
Fe2O3 also increases the strength and hardness like Cr 2O3 and ZnO, but is definitely
lower than Cr2O3 and ZnO. So Fe2O3 is typically added in the transition layer.
Other fillers
Quartz powder, aluminum oxide powder, WA, GC etc are hard to separate from
diamond and CBN. Also recycling diamond is a little bit hard, so is not widely used
at home and abroad. However, these abrasives are added, they can increase the
grinding performance. Technical conditions of various fillers and their role is given
below in the Table.2 and 3.

Table.2 Technical conditions of various fillers

Name Color Chemical Purity Densit Granularity
formula % y
g/cm3
Copper Rose red Cu 99 8.92 F200 to fine
powder
Aluminum Silver Al 99 2.7 F200 to fine
powder white
Iron Gray Fe 99 7.86 F200 to fine
powder
Zinc oxide White ZnO Industri 5.6 F200 to fine
al pure
Iron oxide Red F2O3 99.5 5.8 F200 to fine
Chromium Green Cr2O3 98.5 5.2 F200 to fine
oxide
Graphite Ink C 95 2.52 F200 to fine
Molybden Blcak MoS2 95 4.8 F200 to fine
um
disulfide

44
Table.3 The rote of various fillers

Nam Densit Meltin Main function

e y g
g/cm3 point
/˚C
Cu 8.93 1083 Improve bond strength, electrical conductivity
and thermal conductivity.
Al 2.70 660 Compared with Cu, it can reduce the importance
but the heat resistance is poor.
Ag 10.5 960 Better conductivity than Cu, used electrolytic
grinding wheels.
Cr2O3 5.2 2435
ZnO 5.6 1975 Improve strength, hardness, heat resistance, have
certain polish ability.
F2O3 5.24 1565
Zr .49 1852 The melting point and hardness are higher than
Co 8.9 1492 Cu, and the thermal conductivity is better than
oxide, which can improve the wear resistance,
hardness and strength of the grinding wheel.
SiO2 2.65 1710
Al2O3 3.96 1850 Improve heat resistance and hardness
SiC 3.20 1627 Can reduce the grinding wheel blockage, and it is
auxiliary abrasive effect.

CURING PROCESS FOR FILLER

Lei Guo Study of the Influence of Nanosized Filler on the UV-Curable Resin
Bonded Diamond

As one of the most broadly employed machining process, abrasive machining is a

45
complex material removal process in which a number of abrasive grains randomly
cut material off from the workpiece. Common examples including grinding,
lapping, honing and polishing can be all categorized to abrasive machining process.
In the manufacturing of abrasive tools like grinding wheel and lapping plate, two of
the most significant components are primarily considered: the abrasive grain and the
bonding agent. Abrasive grains are usually selected from Aluminum oxide, Silicon
carbide, Diamond and CBN in modern industry, while metal bonding agent and
resin bonding agent is the most widely used matrix material.
development on rapid prototyping, the ultraviolet (UV) curing technology has been
applied at a wide range in manufacturing. In this research, the UV curing techniques
was introduced into the fabrication of resin bond abrasive tool. In order to optimize
the time consuming, reduce the energy cost of the traditional manufacturing process
and improve the machining performance of the tool, the thermosetting resin agent
was replaced with UV light-curable resin.

To verify the manufacturing feasibility and examine the machining performance of

the tool, an UV light-curable resin bond grinding wheel was developed with
diamond as the abrasive grain. A group of comparative experiments on ceramic
workpiece was carried out to study the machining capacity of the tool, in terms of
surface finishing and material stock removal. Moreover, nanosized alumina particle
was selected as a filler additive in the manufacturing process in order to improve the
material properties of the resin matrix, and strengthen the bonding between the
matrix and the diamond grain. Interestingly, the result showed that the utilization of
nanosized alumina filler influenced not just the manufacturing of the tool, but also
the performance of the tool in a very positive way.
In order to determine the influence of filler loading on the bonding mechanism of
each single diamond grain, a theoretical force model was established based on
elastic mechanics to quantitively describe the retention capability of the resin
matrix, in terms of compressive stress generated from the shrinkage of resin.
Because of the micron scale of diamond grains in resin matrix, it is hard to
experimentally verify this force model. Therefore, a numerical model was also
developed based on FEM simulation to validate the reliability of above-mentioned
force model. A series of calculation and simulation were carried out to
comparatively study the retention force on each diamond grain in pure resin matrix
and filler loaded resin matrix. The results obtained are consistent with reasonable
errors that could be explained by the difference in application conditions of each
model. From a perspective of process prediction, these models could provide not
just a direct output including matrix volume shrinkage and compressive force
generated on each diamond grit, but also an indirect output as the tool’s machining
capacity that largely determined by diamond retention.

46
Influence of Nanosized Aluminum Dioxide Filler Additive
Materials Prepare
The resin used for this study was provided by DYMAX (Light Weld® 425 optically
clear structural adhesive, 431 Ultra-Light Weld® Versatile Glass-to-Metal Bonding
Adhesive), both of the uncured and cured properties from supplier are shown below
in
Table 4.1
Table 4.1 Material specification of the UV-curable resin From previous studies of
the filler-loaded resin matrix, the mechanical properties of filler-resin composites
basically depend on the filler content, size and morphology
Table 4.2 Specifications of the resin-bonded diamond composites

The average size of alumina (α-Al2O3) fillers used in this study was 0.5 µm, and
the diamond abrasive grain used was supplied by Engis Corporation and sized at 12-
22 µm. Table 4.2 showed the specifications of the diamond resin composites filled
with alumina filler in this study. Diamond concentration of a diamond tool means
the weight of the diamonds in each cubic centimeter of the diamond tool, and it is
an important feature of diamond tools that greatly influencing their abrasive
machining efficiency.

47
Figure 4-1 DYMAX 5000-EC UV Curing Flood Lamp
4.1.2 Methods
The composites of UV-curable resin, abrasive diamond, and alumina filler was
uniformly mixed together in vacuum condition to remove the air bubbles which
could be created during the stirring process. The prepared diamond composites in
liquid form were injected into different shapes of mold and then processed to the
exposure of light primarily in the UV range (320-390 nm wavelength). Fig. 4-1
shows the UV curing system used in this research, and the process of UV curing
could be seen in Fig. 4-2 below.

Figure 4-2 Manufacture process of UV light-curable resin bonded diamond plate

4.1.2.2 Curing Depth of the Resin Composites
The mixed composite was injected into a nontransparent “cup” mold with 10 mm

48
inner diameter and a depth of 20 mm. All of the samples were cured under UV light
for 60 seconds and then left for 24 hours. The samples were cleaned as to remove
the uncured portion of the composites and then left at room temperature till dry. The
thickness of the cure depth of the samples were measured with caliper.
4.2 Results and Discussion
4.2.1 Cure Depth of Resin-Diamond Composite
Cure depth is a major issue for light-cured resin diamond composites since the resin
is partly translucent and scatter light, light penetration decreases as the resin
thickness increased. This is due to the absorption and scattering of light by the
diamond particle, the 59additives and porosity of the composites. Since the resin in
this study is UV-reactive, the state and structure of the resin would be affected
around the range of UV light wavelength due to the polymerization of the
monomers. Meanwhile, the interfacial bond between the diamond and resin, the
Al2O3 filler and resin would also be affected because of the volume shrinkage of
the composites. All of these factors mentioned above would influent the light
transmittance of the uncured composites and lead to an erratic fluctuation. Hence,
the visible light wavelength range from 450 nm to 800 nm was selected for light
transmittance test. Figure 4-3 shows the transmittance of uncured resin-diamond
composites with different ratios of Al2O3 filler within the range of visible light
wavelength. The figure indicates that more than 95% (1 -T %) of the light was
absorbed and scattered by the resindiamond composites, regardless of Al2O3 filler
loading. When there is no filler introduced, the transmittance value of the
composites float between 3.0% and 3.5%, and it approaches to 4.0% in 450 nm
wavelength. The transmittance value drops significantly down to 2.5% when the
resin-diamond composites is filled with Al2O3 filler, and the continuous decrease of
the transmittance is attributed to the increase of the filler loading in the composites.
The lowest transmittance value reaches 0.75% when the filler loading was 7.5%wt.

Figure 4-3 Visible light transmittance of the uncured composites with different
ratios of Al2O3 filler

49
Figure 4-4 Thickness of the cured resin diamond composites with different loading
of Al2O3 filler
Figure 4-4 shows that the cured depth of the composites with different ratios of
Al2O3 filler. It is found that the increase in filler loading leads to the decrease in
cure depth. This can be explained that the increase in filler loading increased the
turbidity of the resin diamond composites, then the light transmittance decreases as
a result. Most of the light is absorbed and scattered by the very top layer of the
composites to initiate the polymerization. The light penetration decreased as the
turbidity of the composites increases, and the lower layer could not absorb enough
energy to intimate the reaction. It can be established that the diamond abrasive
concentration and filler loading proportion significantly affect the cure depth of the
resin-diamond composites, the higher filler loading leads to an increase in
composites turbidity and decrease in light transmittance, and then reduce the cure
depth as a result.
4.2.2 Hardness of Cured Resin-Diamond Composite
The hardness of the cured composites is a key factor influent work performance of
resin bonded abrasive tools. The tool undergoes varieties of forces during the
machining process, certain hardness could keep the grain in the situation of scraping
or rolling, thereby affect the material removal rate and surface condition of the
workpiece. Figure 4-5 shows that the Vicker’s hardness values of the cured resin-
diamond composites with different ratios of Al2O3 fillers, it can be established that
the cured resin diamond composite with Al2O3 filler demonstrate significantly
higher HV when compared to the composites without Al2O3 filler (50%-100%
higher), and the HV values also increases constantly as filler loading increases.
Based on Fig. 4-5, the HV value of the composites with 2.5% wt., 5.0% wt., 7.5%
wt. and 10.0% wt. of Al2O3 filler could reach 15.4, 18.2, 19.7 and 20.2 kgf/mm2
respectively, and the unfilled composite indicates a lower HV value at 10.4
kgf/mm2 . Al2O3 filler particles are stiffer and more brittle than the resin matrix,

50
therefore, the increased ratio of Al2O3 filler contributes to an increase on HV value
of the cured composite.

Figure 4-5 Hardness of the UV resin-bonded diamond composites with different

loading of Al2O3 filler
4.2.3 Ultimate Tensile Strength
Figure 4-6 shows the ultimate tensile strength of the resin-diamond composites
filled with different ratios of Al2O3 filler. The highest strength of the cured
composite reaches 45.92 MPa at Al2O3 filler loading of 10 wt. %. In this research,
it can be established that the mechanical properties of the resin-diamond composite
is related to the filler loading, the tensile strength values of different composites are
34.76, 39.98, 42.14, 44.73 and 45.92 MPa, respectively.

51
Figure 4-6 Tensile strength of the UV resin-bonded diamond composites with
different loading of Al2O3 Statistically, the tensile strength value is increased as
filler loading increases within a particular range in our study. The adequate
distribution of the nanosized Al2O3 particle in the resin acted as a reinforce
material and improved the structure of the composites, and then led to the
improvement of the ability to sustain higher stress. Since the continuous increasing
loading concentration of filler would also affect the structure of the resin matrix at
some point. Further research is need to determine the appropriate range of filler
loading concentration.
4.2.4 Worn Surface Microscopy Observation
Based on a number of microscopy observations of the worn surface of UV resin
bonded diamond composites, nearly all of the diamond bond conditions can be
summarized as the figure shown below.

Figure 4-7 Diamond bond conditions in cured resin composites

a) The abrasive diamond was bonded in the cured resin and has not started to
perform as an active abrasive particle;
b) The sharp tips of the diamond revealed as the composites worn out because of the
different wear resistance and material strength of resin and diamond. The diamond
particle at this situation could not fully perform as working grains since the limited
contact between the tips and the workpiece;
c) Active abrasive diamond. Nearly half of the particle embedded in cured resin, the
bond between the resin and diamond helps to hold the grain so the other half of the
particle could work as a fixed micro cutting tool;
d) Partial breakage abrasive diamond. As the machining process continues, some of
the diamond might be broken during the machining process since the particles work
under the complicate force involved condition, in terms of wear compression,
shear,etc. Although the particle was broken in this condition, on the other side, the
worn edges and blunt tips had been took away by fluid and new sharp edges
generated due to the break.

52
e) Breakage diamond particle. The larger piece of the broke particle was pulled out,
however, the small piece of the particle still bonded to the composites. Since the left
piece of the diamond is embedded in the pull-out hole and no edges or tips headed
out from the composites, the breakage diamond in this condition could not be
considered as effective working particle.
f) Pull-out hole. The diamond particle was pulled out and a hole left in the
composites, these holes provided the space to keep the break particle pieces,
material chips, working fluid, etc. as to change the hydrodynamic performance
between the workpiece and abrasive tool, and affect the work efficiency positively.
The different types of diamond bond conditions in cured resin-bond composites can
be seen in Figure 4.8 and Figure 4.9. Based on the comparison of worn surface
microscopy between filler loaded and non-filler loaded resin bonded wheel, it is
obvious to see that more rough traces and marks were generated on the surface of
non-filler load wheel, a large number of diamond particles has been pulled out and
the cured resin matrix worn a lot. In contrast, more active abrasive diamond grains
in condition (b), (c) and (d) is found on the surface of the filler loaded grinding
wheel, and the wear traces and material loss is not as serious as the former one.
Since all the working conditions were the same, this difference indicates that the
diamond grain embedded in the filler loaded wheel is relatively harder to be pulled
out during machining, and a better wear resistance could be achieved through filler
loading. It has been revealed that the work efficiency of abrasive tool is
significantly affected by the properties of bonding matrix and abrasive grain
retention. In this study, a lap grinding experiment was also carried out to examine
the influence of filler loading in machining process of diamond abrasive tool.

Figure 4-8 Diamond abrasive conditions in cured resin-bond composite (a, b)

53
Figure 4-9 Diamond abrasive conditions in cured resin-bond composite (c, d, e, and
f)

Figure 4-10 Surface roughness of workpiece after machining

4.3.1 Surface Roughness of Workpiece
It can be clearly seen in Fig. 4-10 that the workpiece machined on the filler loaded
plate obtained an outstanding improvement in surface roughness. The average
roughness value of the two tests represented a same trend that they dropped down
rapidly in the first 4 minutes from 0.40μm to 0.085μm and 0.124μm respectively,
then the drop rate reduced significantly and the roughness approached to 0.080μm
and 0.1220μm at 6 minutes. After 6 minutes, the roughness fluctuated around
0.075μm and 0.117μm and the lowest value of each condition was reached at 10
minutes (0.0752μm and 0.1162μm). The near 30% improvement of the surface
quality can be firstly explained that the alumina filler also played as an abrasive
particle during the lap grinding process. Since the particle size of the alumina filler
is smaller than the diamond abrasive particle, the chips taken off by indentation
from the filler loaded plate is much smaller than the ones from non-filler loaded
plate. Moreover, the free alumina filler particle that pulled out from the resin matrix

54
caused micro-polishing between the abrasive tool and workpiece, which also
contributed to a better surface quality.

doi:10.4028/www.scientific.net/KEM.487.204.
In view of the problems of the computer aided design in the abrasive tool
manufacturers, the manufacturing process flow of the resin-bonded diamond
abrasive tool and the related factors affecting the quality were analyzed. The
principle of CAD technology based on quality control was proposed. The key
technologies of the abrasive tool CAD system based on quality control were put
forward, including the computer aided formula design, the process flow design
based on the parametric templates, the quality control technology based on the
parameter constraints, etc. Based on these, the resin-bonded diamond abrasive tool
CAD system based on quality control was developed.
The development environment and implementation methods of the system were
proposed. This paper takes the resin-bonded diamond abrasive tool as the object and
studies the abrasive tool CAD technology based on quality control. The aim is to
solve the problem of quality control in the abrasive tool CAD system.

The Principle of Abrasive Tool CAD Technology Based

on Quality Control
In the abrasive tool CAD technology based on quality control, all the process
parameters must be set according to the principle of quality, and the performance of
design results must be checked real-timely. The technical principle is shown as
fig.2. The abrasive tool CAD system mainly includes computer aided formula
design module, manufacturing process flow design module and quality control
module. The formula design module takes the basic information database and
formula parameter database as data sources. The process flow design module takes
the manufacturing process parameter database and parametric template library as
data source. The calculation of parameter-quality relationship, the performance
examination and the other functions can be fulfilled in the quality control module.
Each design module will call the functions of quality control module to ensure that
the process parameters can meet the predetermined requirements of performance.

55
Fig.3The interface of curing process design
Development and Realization of The System.
Based on the above analysis of the technologies and principles, the resin-bonded
diamond abrasive tool CAD system based on quality control has been developed.
The system has been applied in an abrasive tool manufacture Co., LTD. The system
is designed and developed by the architecture of C/S. The Visual Studio
2005(C#.NET) was taken as the development environment, and the SQL Server
2000 was used to establish the databases of system. The Web Service technology
wasadopted to develop the parameter constraints function library. The main
function modules of system include system management, user management,formula
design, confecting and mixing process design, molding process design, curing
process design, quality inspection, etc. Theinterface of curing process design is
shown in fig.3.
Aiming at the requirements of digital design proposed by the abrasive tool
enterprises, the CAD technology of resin-bonded diamond abrasive tool based on
quality control is investigated and the corresponding CAD system is developed. The
technology principles of the system are analyzed. The computer aided formula
design, the process design based on parametric template and the quality control
based on parameter constraints are researched and applied, which brings good
effect. This technology can greatly improve the design and manufacturing level of
the abrasive tool enterprises. And, it also has certain reference significance for
developing similar abrasive tool CAD system.

United States Patent Goyal et al 14/415,074 Rupid curing of resin bonded

grinding wheel
In the manufacturing of grinding products such as resinoid grinding wheels, which
are designed to perform heavy duty tasks such as metal cutting made with an

56
abrasive material which is intimately mixed with the bonding ingredients and
temporary binders. The bonding ingredient consists of such compounds as are
necessary to combine to form the required resinoid bond during curing. The
ingredients are mixed and pressed into the required shape.
U. S. Pat. Nos. 4,150,514 and 4,404,003 disclosed the process in which the mixture
was prepared by blending of refractory particles, binder and filler. This mixture was
subjected to microwave energy at about 2.45 GHz. This heats the charge to
temperature within the range of about 35-120 C. this is called the preheating process
of the grinding wheel mix. Then this preheated mix was transferred to molds which
were then placed between the platens of a hot mold press and mold was subjected to
pre-curing heating step in accordance with conventional procedures. The curing is
done using electrical resistance heating or oil firing or gas firing as per desired time
temperature profiles. These patents used the microwave only for the preheating of
the mixture which provides fluidization and minimizes the degree of pressure
required for the production of any given density of resin abrasive mixture. The final
curing of the grinding wheel was followed by the conventional route.
Example: a green compacts sample of depressed resinoid grinding wheel (DP1), 100
mm diameter, 5 thick and 15 mm hole diameter, weighing 90 g was placed between
12 mm thick graphite susceptors weighing 200 g each. The graphite sample holders
were made to hold the samples of green grinding wheels to fit snugly in the sample
and with tiny holes in the walls of the suseptors. These green grinding wheels
consisting of alumina grains mixed with phenolic resins and fillers were cured at
220 C. in 700 W microwave system within 90 minutes. To obtain a substantially
uniformly cured depressed resinoid grinding wheel

57
 3. Effect of copper filler of resin-bonded diamond composites on the
wear behaviours under a dry condition

2. Experimental procedures
Specimens
Phenolic resin-bonded diamond composites with three different amounts of copper
filler were fabricated for experimental studies. Table 1 gives the speci®cations of
the diamond composites used. All of the specimens contained 10 vol% PTFE to act
as lubricant. The process of manufacturing these composites used compression
moulding technology. The size of the rectangular diamond composites fabricated
was 40 mm * 10 mm * 5 mm. Friable nickelcoated diamond of 120/140 US mesh
was used at 90 concentration (3.96 carats cmÿ3 ).
Table 1
Specifications of the diamond composites

58
Fig. 3. Transverse rupture strength of the resin-bonded composites.
3.1. Strength of the resin-bonded composites The transverse rupture strength for
three types of resinbonded composite are given in Fig. 3. It can be seen that the
transverse rupture strength value of diamond composite increases with the increase
of copper filler. This is attributed to the appearance of the dendritic structure of
copper powders, which leads to mechanical interlocking with the resin. Hence, it
causes the strength of the diamond composites to increase with increase of the
copper filler. Further, the resin bond containing diamond particles had a lower value
of transverse rupture strength than that of those without diamond grits. The lower
hardness, and the higher wear loss of the bond matrix. It indicates that 30±40 vol%
Cu was the most effective filler in reducing the wear loss of the resin-bonded
diamond composite.

Fig. 5. Wear volume loss of the resin composites.

From the above results, understanding and additional knowledge regarding the low
grinding ratio of the resinbonded diamond wheel during the dry grinding of P10
tungsten carbide is needed. Because the phenolic resin is generally subjected to
temperatures of above 200±2308C during grinding, it will suffer dissolution and
deterioration, thereby causing the diamond abrasive to reduce its retention on the
bond. In this study, filler materials such as copper, graphite, PTFE, etc. are added to
the phenolic resin to improve heat dissipation, lubrication, abrasion resistance,
hardness, thermal stability, and tensile and compressive strengths. However, the
fillers cannot improve the thermal dissolution temperature of the resin. The wheel

59
surface temperature during the dry grinding of P10 tungsten carbide in the test can
reach about 350±6008C (see Fig. 14). In this instance, the phenolic resin will be
rapidly deteriorated, thereby signi®cantly reducing the diamond grit retention on
the resin bond, which causes the abrasives to be easily plucked out from the bond.
Moreover, when the grinding temperature is above 600±6508C, the diamond
particles will also start to suffer from oxidation, reducing their impact strength,
hardness, and abrasion resistance.

Fig. 13. Grinding ratio obtained for specimens AD, BD, and CD during the dry
grinding of P10 carbide.
These lead the wheel to produced poor grinding ratio, and in an extreme case, cause
the wheel to burn or fail. Hence, in order to improve the grinding ratio during the
dry grinding of P10 tungsten carbide, resins with high thermal resistance such as
polyimide are used. In addition, comparing the wear loss in Fig. 5 with the grinding
ratio in Fig. 13, it can be seen that the wear loss of the resin-bonded diamond
composite obtained from the dry abrasion test is in good agreement with that from
the dry grinding test. This indicates that 30 vol% Cu filler produces the best results
in the reduction of wear.

60
Fig. 14. Average wheel surface temperature and the average wheelworkpiece
contact temperature produced for specimens AD, BD, and CD during the dry
grinding of P10 carbide.
1. The transverse rupture strength of resin-bonded diamond composite increases
with increase of the amount of copper filler.
2. Pull-out of copper fillers in the dry abrasion test seemed to be the main wear
mechanism explaining the high wear loss for the resin composite with 20 vol% Cu
filler. The worn surface of the resin composite with 40 vol% Cu filler exhibits a
great number of abrasive traces and a large amount of plastic deformation of the
copper fillers. The resulting wear loss is relatively lower.
3. 30±40 vol% Cu was the better effective filler in reducing the wear loss of the
resin-bonded diamond composite in dry abrasion against alumina sandpaper. The
resulting worn surface occurs due to the relatively higher proportion of breakage
particles and the smaller number of grits pulled-out.
4. A resin-bonded diamond wheel with a greater amount of copper filler during the
dry grinding of P10 carbide results in a relatively higher proportion of protrusive
particles and partial breakage grit and a smaller number of pull-out holes occurring
on the bond, which leads the wheel to produce relatively higher grinding forces.
However, the grinding temperature generated for the wheel with 30 vol% Cu filler
is relatively lower, which may be the result of a balance between the heat
dissipation of the copper filler and the tangential force produced during dry
grinding. The resulting grinding ratio is relatively higher, and is in good correlation
with the results of dry abrasion testing.

4. Performance of powder filled resin bonded wheels in the zvertical dry

grinding of tungsten carbide
Grinding performances of several resin bonded diamond wheels containing copper,
silicon carbide and carbon black fillers in the vertical dry grinding of cemented
tungsten carbide are studied. The experimental result showed that the resin bonded
diamond wheel with the greatest amount of copper filler resulted in a relatively
higher proportion of protrusive particles and partial breakage grits and a smaller
number of pull-out holes occurred on the bond surface, which leads the wheel to
produce relatively higher grinding forces and temperatures. The resulting grinding
ratio is relatively low. The grinding forces and temperatures produced for the wheel
containing silicon carbide and copper filler increase with the increase of the
proportion of silicon carbide filler. Small amounts of carbon black filler added into
the wheel containing copper filler can obtain the effect with the decrease of the
grinding forces and the wheel wear. However, the grinding temperature produces
during the dry grinding is still relatively high. Low grinding ratio produced in the
vertical dry grinding is mainly attributed to high temperature and the grinding
mechanism.

61
Several of different resin-diamond wheels were fabricated for experimental studies.
Table 1 gives the specifications of the diamond wheels used. Fillers added into resin
bond were mainly copper (Cu), silicon carbide (SiC), and carbon black (C). all of
the wheels contained PTFE to act as lubricant. The process of manufacturing these
wheels used compression molding technology. Cup-type (11A2) grinding wheels
with diameter of 85 mm and rim width of 8 mm were used in the test. Friable
nickel-coated diamond of 120/140 US mesh was used at 90 concentration (3.96
carats cm-3). Grinding test of the resin diamond wheels were performed on a vertical
CNC machining center, its engage

Discussion
From the above results, two modes are proposed to describe low grinding ratio
produced by the resin-bonded diamond wheel in the vertical dry grinding of P10
tungsten carbide. First, because the phenolic resin is generally subjected to
temperatures above 200-300 C during grinding, it will suffer dissolution and
deterioration, thereby causing the diamond abrasive to reduce its retention on the
bond. In this work, filler materials such as copper, silicon carbide, etc. Are added to
phenolic resin to improve abrasion resistance, hardness, or thermal stability.
However, the filler cannot improve the thermal dissolution temperature of the resin.
The wheel surface during the dry grinding of P10 tungsten carbide in the test can
reach about 300-600C, the diamond grits will also start to suffer from oxidation,
reducing the diamond grit retention on the resin bond. Moreover, when the grinding
temperature is above 600-650C, the diamond grits will also start to suffer from
oxidation reducing their impact strength, hardness and abrasion resistance. These
led the wheel to produce poor grinding ratio, and in an extreme case, cause the
wheel to burn or fail. Hence, in order to improve the grinding ratio during dry
grinding of P10 tungsten carbide, the resins with high thermal resistance such as
polyimide or metal bond and vetrified bond can considered.
The other mode is that a maximum undeformed chip width generated in vertical
grinding equals a depth of cut of the wheel, and a maximum undeformed chip
thickness, hm,obtained at the middle of the vertical step being cut for a traingular
undeformed chip cross-section is

62
Where C is the number of cutting points per unit area of the wheel surface and r the
ratio of chip width to average undeformed chip thickness. Hence, the depth of cut
used during the vertical grinding must be smaller than the protrusive height of
diamond grit on the wheel surface. Otherwise, the workpiece will shear the bond to
break the structure of the wheel, causing the wheel to wear rapidly. Besides, the
cutting load in vertical grinding is concentrated near the edge of the wheel. In this
work, the diamond grits used are 120/140 US mesh size, and their protrusive height
measured after dressing are about 0.03-0.04 mm (about one-fourth to one third of
the grit diameter). hence, when using the larger depth of cut of 0.05 or 0.1 mm
during grinding, the wheel will be subjected to heavy shear and broken by the
workpeice causing the wheel to wear rapidly. In this situation, wheel will produce a
very low grinding ratio.
Conclusion
1. A resin bonded diamond wheel with a greater amount of copper filler during the
dry grinding P10 carbide results in a relatively higher proportion of protrusive
particles and partial breakage grit and a smaller number of pull-out holes occurring
on the bond, which leads the wheel to produce relatively higher grinding forces and
temperatures. The resulting grinding ratio is relatively low.
2. The grinding forces and temperatures produced during dry grinding for the wheel
containing silicon carbide and copper filler increase with increase of the proportion
of silicon carbide filler. This would cause the wheel to produce a large number of
pull-out holes on the worn surface, which causes the wheel to produce a low
grinding ratio.
3. Small amount carbon black filler added into the wheel containing copper filler
can obtain the positive effect with the decrease of the grinding forces and the wheel
wear loss. However, the grinding temperature produces during dry grinding is still
relatively high.
4. Low grinding ratio obtained in the vertical dry grinding of P10 tungsten carbide
is mainly attributed to high temperature, thereby leading the resin degradation and
reducing the diamond retention on the bond, and the vertical grinding machanism,
making the workpiece to shear the wheel. Hence, the wheel produces a great
number of particles plucked out from the bond, causing the wheel to wear rapidly.

5. Filler in resin diamond 3D printing wheel

3D printing is known to be based on a layer-by-layer mode and can be applied to
manufacture a component with complex structures. This technique has drawn
significant attentions for applications in a variety of fields, including aviation,
medical, biotechnology, electronic, and oceanography. Recently, it has also been

63
proposed for manufacturing diamond tools. For example, Yang et al. [Z. Yang, M.
Zhang, Z. Zhang, A. Liu, R. Yang, S. Liu, A study on diamond grinding wheels
with regular grain distribution using additive manufacturing (AM) technology,
Mater. Des. 104 (2016) 292–297.
12] applied the additive manufacturing technology to design a metal bond diamond
grinding wheel with regular grain distribution. Moreover, Tian et al. [] C. Tian, X.
Li, S. Zhang, G. Guo, L. Wang, Y. Rong, Study on design and performance of
metal-bonded diamond grinding wheels fabricated by selective laser melting (SLM),
Mater. Des. 156 (2018) 52–61.] used the selective laser melting (SLM) method to
fabricate porous metalbonded grinding wheel. Tanaka et al. and Huang et al.[14,15]
investigated resin bond diamond grinding wheel by stereolithography (STL)
process. However, 3D printing to prepare a diamond wheel with internal connected
cooling holes to improve grinding performance has rarely been studied. Herein,resin
bond diamond grinding wheels with arrayed internal cooling holes were prepared by
the SLS technique. The composition of the resin bond of the diamond wheel was
optimized. Moreover, the performance of the 3D printed diamond wheel with
different internal cooling holes was investigated.

2. Experimental
The details of the resin, pore former (Glass bubble), filler (white corundum), and
diamond grits for the 3D printing are presented in Table 1. Furthermore, Table 2
lists the specification of the printed wheel with characteristics of internal cooling
holes. Fig. 1 shows the Scanning Electron Microscopy (SEM) images of nylon,
diamond grit, glass bubble, and white corundum powders.

Microstructure and mechanical properties of the 3D printed diamond wheel

Fig. 5(a) and (b) show the optical microscopic images of the internal cooling holes
with the diameters of 1.5 mm (G2) and 2.5 mm (G3), respectively. Fig. 6 illustrates
the surface morphology of printed samples, indicating that the diamond grits, white
corundum powder, and glass bubbles are evenly dispersed in the printed matrix. The
hardness
and bending strength of the grinding wheel of the 3D printing are shown in Fig. 7.
With the addition of the white corundum powder in the bond, the hardness
increased. This can be explained by the model of particle reinforced polymer
composite as represented by Equations (1) and (2) proposed by Liang et al. [17]:

64
Fig. 6. The surface morphology of the printed sample.

parameters related to the particle diameter distribution and shape as well as

interfacial adhesion, the filler volume fraction, and the matrix Poisson's ratio,
respectively. Zorzi and Perottoni [18] derived the correlation between the Vickers
hardness, Young's modulus, and Poisson's ratio by the instrumented indentation test,
shown by Equation (3):

65
Equations (1) and (2) show that the Young's modulus of grinding wheel increases
with increasing amount of added white corundum. Therefore, the hardness increased
in accordance with Equation (3). However, the bending strength slightly changed.
The white corundum is popular reinforcement filler in the resin bond diamond
wheel. Due to the low content of the white corundum (2 wt%), the reinforcement
effect is limited in this study. Fig. 8 illustrates the fractured surface of 3D printed
wheel samples. The diamond grits, white corundum particles, and glass bubbles are
buried in the nylon matrix. The concentration of diamond grits is much higher than
that of the white corundum powder and glass bubble, thus white corundum particles
and glass bubbles are not easy to be identified such as diamond grits.

Fig. 8. SEM images of the sample fractured surface: (a) (b) without the addition of
white corundum; (c) (d) with the addition of white corundum.

doi:10.4028/www.scientific.net/AMR.893.649
Resin-bonded diamond grinding tools produce a high grinding ratio [7S. Y. Luo, Y.
S. Liao, C. C. Chou, J. P. Chen. Analysis of the wear of a resin-bonded diamond
wheel in the grinding of tungsten carbide. Journal of Materials Processing
Technology 69(1997) 289-296.]. In order to obtain the auxiliary materials in the

66
resin abrasive with the best dosage and make the resin abrasive tool has good
comprehensive properties, the polishing abrasive industry, as well as some
commonly used filler toughening by changing the amount to study the consumption
of the auxiliary materials how to impact the grinding performance of the diamond
grinding tools was focused in this paper.

When NaHCO3 content is 16%, the grinding rate was substantially increased by
99.12% than those did not add NaHCO3 to the maximum. But while the content less
than 16%, the grinding rate decreases along with increasing its content. It may be
because that the strength and hardness of the grinding tool reduced and the wear
resistance also decreased after adding NaHCO3, thus cause the abrasive abrasion
increased. But when NaHCO3content increased to 16%, the porosity of the abrasive
increased due to its pore-forming effect, and the wear debris can discharge smoothly
i
n the grinding process, also it can effectively reduce the ablation of grinding tool,
which reduces the abrasive removal rate. While the strength and hardness of the
abrasive have substantially reduced, its sharpness was also reduced and which result
in the grinding efficiency decreased.

Grinding performance analysis of the different Zn

O content.
The grinding experimental data can be shown in Table 2. When ZnO content in the
fo
rmulation is 3%, the grinding rate increases by 43.48% than those without adding
ZnO to the maximum, and it will gradually reduce if ZnO content continues to
increase. The reason may be that the abrasive strength and heat resistance improved
after joining ZnO, so as to improve the grinding efficiency. But when ZnO content

67
continues to increase to make the strength and hardness too high, it will affect the
abrasive self-sharpening thus resulting in lower grinding ratio.

Conclusions
The auxiliary materials were successfully researched by using NaHCO3, ZnO and
NBR in abrasive tools. The addition of NaHCO3 will reduce the Rockwell hardness
and bending strength of the abrasive tool, and with the increase of it in the
formulation, the hardness and strength of the abrasive tool decline seriously;
meanwhile, although increase the content of NaHCO3will improve the abrasive
wear resistance, but the abrasive grinding efficiency was also decreased. While
increasing
the content of ZnO, the abrasive bending strength increased, while weak hardness,
and while ZnO content reached 3%, the grinding rate increased by 43.48% and the
grinding efficiency also improved; but the abrasive’s self-sharpening was reduced,
the
reby reducing the abrasive grinding performance. Adding NBR in abrasive
formulation can reduce the Rockwell hardness and bending strength of the abrasive
tool, and the higher the content of NBR, the greater the abrasive hardness and
bending
strength decline; In addition, the addition of NBR could improve the abrasive wear
resistance, but it would reduce the sharpness of grinding tool, thus reducing the
grinding efficiency.

COMMON FILLERS FOR SUPER-HARD RESIN ABRASIVES.

Influence of auxiliary abrasive on the resin bond used in diamond tools

(a) (b) (c)

68
The resin bond abrasive tool is prepared by hot pressing. The resin, fillers, auxiliary
abrasives and diamond were mixed. The Fig.(a)showed that with increasing the
content of TiO2, It can effectively improve the mechanical properties of the
abrasive tools during the preparation of resin bond abrasive tools added the right
amount of TiO2. fig.(b) It shows that the Rockwell hardness with the increase of
CeO2 content has been in a slight increase or decrease, namely it has little effect on
the hardness of the resin bonded abrasives. But its content has a great influence on
the bending strength of the resin bond abrasive tool the bending strength increased
when its content more than 1%, it was still relatively low compared with no CeO2.
CeO2 as a filler mainly in order to improve the polishing of abrasive, but it will
reduce the strength of the resin bonded abrasives, thus affecting the abrasive life.
Fig.(c) The Rockwell hardness and bending strength of the sample with different
content of SiO2. It shows that the Rockwell hardness and bending strength has a
similar change, namely with the increase of SiO2 content, the hardness and strength
declined firstly, and then increased. As auxiliary abrasives, these three oxides with
dissimilar hardness have diverse effect on the resin bond abrasive tools. The alloy of
TiO2 degrades the Rockwell hardness and bending strength of abrasive tool and they
fall down to minimum when the content of TiO2 is 5%; but it’s addition enhance the
holding force of force the resin bond, and the abrasive wear resistance increased.
Enhancing the CeO2 will decline the strength of the diamond tool, but it’s
contributes less to the hardness of the abrasive tools. Addition CeO 2 develop
polishing performance of the abrasive but shelf life of the abrasive tool has reduced.
Wear resistance and corrosion resistance of the abrasive tools are consummated by
SiO2 as a type of polishing abrasive. Although, complement of SiO 2 degrades the
bending strength of the abrasive tools. Moreover, addition of SiO 2 is not possible to
intensify the hardness until it is content is more than 7%.

Characteristics of Multifunctional, Eco-Friendly

Lignin-Al2O3 Hybrid Fillers and Their Inflfluence on the Properties of
Composites for Abrasive Tools
Klapiszewski, Ł., Jamrozik, A., Strzemiecka, B., Koltsov, I., Borek, B.,
Matykiewicz, D., ... & Jesionowski, T. (2017). Characteristics of multifunctional,
eco-friendly lignin-Al2O3 hybrid fillers and their influence on the properties of
composites for abrasive tools. Molecules, 22(11), 1920.

Abstract: The main aim of the present study was the preparation and
comprehensive characterization of innovative additives to abrasive materials based
on functional, pro-ecological lignin-alumina hybrid fifillers. The behavior of lignin,
alumina and lignin-Al2O3 hybrids in a resin matrix was explained on the basis of
their surface and application properties determined by inverse gas chromatography,
the degree of adhesion/cohesion between components, thermomechanical and
rheological properties. On the basis of the presented results, a hypothetical
mechanism of interactions between lignin and Al2O3 as well as between lignin-
Al2O3 hybrids and phenolic resins was proposed. It was concluded that lignin

69
compounds can provide new, promising properties for a phenolic binder combining
the good properties of this biopolymer as a plasticizer and of alumina as a fifiller
improving mechanical and thermal properties. The use of such materials may be
relatively non-complicated and effificient way to improve the performance of
bonded abrasive tools.

Resin-bonded abrasive products are complex composites consisting of abrasive,

wetting agent (e.g., resole), binder (e.g., novolac), and fifillers (e.g., pyrite, cryolite)
[1]. Several factors inflfluence the properties of the fifinal abrasive tool during the
production process and exploitation. The fifirst stage during production of abrasive
tools is covering the abrasive grains by resole. Appropriate covering of grains by
resole is crucial for homogeneity of the semi-product and the fifinal product [2]. In
the next stage novolac mixed with fifiller is added. Then, the semi-product is
pressed and hardened according to a specifific temperature program. The
appropriate hardening of the semi-product is highly important for the effificiency of
the fifinal product [3]. Hardening of resins in the fifinal product also depends on the
fifillers used. Some of them can accelerate the hardening rate and some of them can
modify this
process [3]. Moreover, the fifillers play a very important role in the work of the
grinding tools, as they collect heat and prevent melting of the resin [4,5]. Inorganic
compounds are broadly used as fifillers. Conjugation of these fifillers, characterized
by polar surface properties, with a non-polar polymer matrix is diffificult [6]. The
use of an organic-inorganic hybrid fifiller may overcome this problem. Moreover,
such hybrid fifillers may increase the thermal resistance and mechanical strength.
This effect may result
from the possible reactions between active groups present in the inorganic and
organic components. Alumina is one of the most commonly used abrasive materials.
In the present study, alumina was used as a fifiller. An Al2O3 fifiller can act as an
additional abrasive and can collect heat. In order to increase the functionality of the
fifinal product, alumina was combined with lignin. Lignin is a natural polymer with
a similar structure to phenolic resins used as binders in abrasive articles. Today,
interest in natural resource polymers is growing due to the depletion of conventional
petrochemical resources [7]. There are already known cases of successful use of
biopolymers such as cellulose in advanced applications [8,9]. Lignin is the most
available material in nature after cellulose [10]. Modifified lignin is a
polarographically active material and in recent years this biopolymer has also found
interesting applications in electrochemistry [11–14]. As an aromatic biopolymer, it
is a potential substitute for the polymers obtained from petroleum, due to its
comparable or improved physicochemical properties and lower manufacturing cost.
The presence of numerous hydroxyl groups in aromatic rings enables its use as a
starting material for the synthesis of a wide range of polymers (such as polyethers,
polyesters, polyethylene and polyurethane) [15]. Literature reports also suggest the
potential use of lignocellulosic materials, including pure lignin and/or
lignosulfonate, as fifillers in a large group of polymers [16–22].

70
The problem of application of lignin to polyolefifins was described in [19–22]. In
case of mixing lignin with phenolic resins, the problem is not associated with the
homogeneity of the polymer-lignin system, but insuffificient mechanical properties
[23,24]. Thus, it is expected that the application of a lignin-alumina hybrid as a
fifiller may improve the mechanical properties of the fifinal product. A very
important aspect of the use of lignin-alumina hybrid as a fifiller is the reduction of
emissions of harmful compounds into the atmosphere, due to the increased thermal
stability of such a system in comparison with phenolic resins and/or lignin systems
[24]. The described biopolymer is also one of the potential low-cost and readily
available sorbents of environmentally harmful metal ions [25,26]. In order to be
used as a sorbent, lignin can be obtained chieflfly as a waste product from the paper
industry and subjected to chemical modifification to increase the number of
functional groups [27]. There is a limited number of reports which describe attempts
to use lignin and/or lignosulfonate in the preparation of advanced inorganic-organic
hybrid materials. The concern is mainly the combination of biopolymers with the
widely used and well-established silica [13,14,21,22,26,28–30]. Direct linking of
natural polymers (lignin and lignosulfonates) with alumina has not been previously
described. The aim of our study was the preparation of new hybrid lignin-alumina
fifillers, which have not
yet been described in the literature. The next step will be to test applications of the
model composites in the abrasive industry. Lignin-alumina hybrid fifillers were
preliminarily tested to establish whether they may serve as new, promising, eco-
friendly fifillers for abrasive tool production. It is expected that such hybrid fifillers
should: (i) reinforce the fifinal composite and (ii) possess higher thermal stability
than lignin itself.
3. Materials and Methods
3.1. Preparation of Novel Lignin-Al2O3 Hybrid Filler
The novel, functional lignin-Al2O3 hybrid materials were prepared by a mechanical
method from commercial alumina (Sigma-Aldrich, St. Louis, MO, USA) and Kraft
lignin (Sigma-Aldrich). Hybrid additives were produced using 8 parts by weight of
lignin with 1, 2, 4 and 6 parts of Al2O3, respectively. To combine the Al2O3 and
lignin, a mechanical process was used whereby the initial powders were ground and
simultaneously mixed using a Pulverisette 6 Classic Line planetary ball mill
(Fritsch, Idar-Oberstein, Germany). The vessel with the materials for grinding was
placed eccentrically on the mill’s rotating base. The direction of rotation of the base
is opposite to that of the vessel, with a speed ratio of 1:2. The three agate balls
inside the vessel move due to the Coriolis force. To obtain suitably homogeneous
fifinal materials, grinding was continued for 6 h. To prevent possible overheating
of the material due to continuous grinding, every 2 h the mill automatically
switched off for 5 min, after which it began operating again. Immediately after
grinding, the lignin-Al2O3 hybrid materials were sifted using a sieve with a mesh
diameter of 40 µm.
3.2. Preparation of Abrasive Composites with Lignin-Al2O3 Hybrids

71
The model abrasive composites were prepared by mixing resole, fifiller, novolac
and abrasive grains, in a ratio of 3:5:12:80 by weight. The proportions of the
components were chosen as the standard values used in the abrasive industry. The
components were mixed using a mechanical mixer at a slow rate of 200 rpm for a
short time (about 3 min)—the process was carried out at room temperature. White
fused alumina with a 120 mesh granulation was used as an abrasive. Novolac
contains 9%
hexamethylenetetramine (hexamine). Firstly, the abrasive grains were covered by
resole, then the mixture of novolac and fifiller was added and homogenized. The
composites prepared this way were formed into cuboids. The samples were then
hardened according to the following temperature program: heating from 50 ◦C up to
180 ◦C, heating rate 0.2 ◦C/min, then heating at 180 ◦C for 10 h.
3.3. Physicochemical and Dispersive-Morphological Characteristics of Lignin-
Alumina Hybrids
3.3.1. Particle Size Distribution
The dispersive properties of the products were evaluated using Mastersizer 2000
(0.2–2000 µm) and Zetasizer Nano ZS (0.6–6000 nm) instruments (Malvern
Instruments Ltd., Malvern, UK), employing the laser diffraction and non-invasive
back scattering (NIBS) techniques respectively. During the experiments, no pre-
treatment was used for breaking down the agglomerates of the investigated
products.
3.3.5. Inverse Gas Chromatography
Surface properties of the hybrid fifillers as well as alumina and lignin were tested by
inverse gas chromatography (IGC). IGC experiments were carried out using a SEA
Advanced apparatus (SurfaceEnergy Analyzer produced by Surface Measurement
System Ltd., London, UK) equipped with a flflame ionization detector. The studied
hybrid fifillers were applied to inert glass beads in a quantity of 1% (200 mg),
placed in a glass chromatographic column (30 cm length, 0.4 cm inner diameter).
The column oven temperature was 30 ◦C, and the temperature of the detector and
injector was 150 ◦C. Dead time was determined by means of methane injection.
Helium (flflow rate 15 cm3/min) was used as the carrier gas. The following test
compounds were used: nonpolar—hexane, heptane, octane, nonane, decane; and
polar—ethyl acetate, dichloromethane, ethanol, dioxane, acetonitrile, acetone

Thus, a hybrid fifiller with a lignin-to-alumina ratio of 8:6 wt/wt has different
surface properties than the other studied hybrid materials, and can behave
differently in the abrasive article. It is reflflected for example in the different

72
rheological properties for composite with a lignin-to-Al2O3 ratio of 8:6 wt/wt
(Table 5). Moreover, this is in agreement with particle size distribution results:
the hybrid with a lignin-to-Al2O3 ratio of 8:6 was characterized by a similar size
distribution to that of alumina (see Section 2.1).

Figure 11. SEM images of novolac + corundum + resole composite (a,b) and
novolac + corundum + resole + lignin-Al2O3 systems with ratios of organic-
inorganic filler equal to 8:1 wt/wt (c) and 8:6 wt/wt (d)
2.7. Scanning Electron Microscopy Analysis of Composites
The structure of composites with hybrid lignin-alumina fillers was fairly
homogeneous. The abrasive grains were well-bounded in all of the studied fillers.
Only some small filler agglomerates can be seen. There were no essential
differences in the homogeneity of the composites depending on the ratio of lignin to
alumina in the fillers. Particularly noteworthy are the SEM images of the composite
without the organic-inorganic hybrid filler, consisting exclusively of novolac,
corundum and resole (Figure 11a,b). The characteristic structures shown in the
images demonstrate the homogeneity of the resulting mixture. The addition
of organic-inorganic materials with appropriate ratios of lignin to alumina did not
significantly deteriorate the morphological and microstructural properties (Figure
11c,d). Only small differencesarise from the variation in the quantity of biopolymer
relative to inorganic material table 6

73
2. Results
2.1. Dispersive-Morphological Properties of Lignin-Al2O3 Hybrids Aluminum
oxide exhibited the presence of primary particles with diameters close to 100 nm,
which showed a tendency to form aggregates (<1 µm). Al2O3 had different
dispersive-morphological properties (see Table 1 and Figure 1a). The particle size
distribution of Al2O3 is very broad (from 142 nm to 955 nm, data from a Zetasizer
Nano ZS apparatus). Addition of lignin slightly increased the particle size
distribution. As follows from the data presented in Table 1, the increased lignin
content in the hybrid filler resulted in a shift of the size distribution of particles
(including primary particles and agglomerates, respectively) to larger sizes.
It should be noted that the commercial Kraft lignin used in the study contains
particles of a wide range of sizes, which indicates the possibility to form large
agglomerate structures. The presence of primary particles and secondary
agglomerates was also confirmed by SEM images. Figure 1a,b present the SEM
images of Al2O3 and lignin, respectively, while Figure 1c,d show images of lignin-
alumina hybrids obtained with the use of different ratios of lignin to Al2O3 (8:1
wt/wt and 8:6 wt/wt respectively). It can be observed that 50% by volume of the
lignin-alumina (8:1 wt/wt) hybrid system was occupied by particles with diameters
smaller than 3.6 µm, while 90% of the sample volume was taken up by particles
with diameters smaller than 5.3 µm. The average particle size in the hybrid system
was 3.3 µm (see Table 1)

Conclusions
The results presented in the framework of this study demonstrate that novel lignin-
alumina hybrid fifillers, which were not previously described in the literature, can
be obtained in a relatively simple way by intensive mechanical mixing of the
biopolymer with Al2O3. The use of lignin-alumina hybrids makes it possible to
obtain fifinal composite abrasive articles with higher plasticity due to the lignin
part, and also better heat conductivity due to the Al2O3. Moreover, it turns out that
the addition of even a small quantity of alumina (lignin-to-alumina ratio 8:1 wt/wt)
can increase the thermal conductivity of lignin, and thus improve the
thermomechanical properties of the final composite used for abrasive tool
production. The inorganic-organic hybrid fillers added to the composition of the
abrasive tool have the most influence on the dynamics of cross-linking at
temperatures of approx.
160 ◦C and the “internal” turbulence process at temperatures of approx. 140 ◦C, by
changing the normal force. It is worth noticing that the addition of lignin-Al2O3

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hybrids notably decreased phenol emission and slightly limited formaldehyde
emission in comparison to commercially used fifiller natural zeolite micro 20 as
well as pure Kraft lignin. The thorough physicochemical analysis of the new hybrid
fifillers has shown that chemical bonds may be formed between the hydroxyl groups
present in both lignin and alumina. Further research will certainly be continued in
this direction, especially with the use of kraft lignin derivatives combined with
alumina using mechanical and chemical methods to increase the interaction between
the precursors. Additionally, the study of the durability properties of the adhesives,
using natural and/or QUV accelerated tests to prevent the ageing effects of
temperature, humidity and UV exposure on the coating will be particularly
important in the near future.

Köbnick, P., Velu, C., & McFarlane, D. (2020). Preparing for Industry 4.0: digital
business model innovation in the food and beverage industry. International Journal
of Mechatronics and Manufacturing Systems, 13(1), 353.

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