Fundamental of

Additive Manufacturing Professional

Elective-2 (19A03603b)
B.Tech (ME) III-II Sem-JNTUA
Unit.1
By
Prof. Eriki Ananda Kumar
ITI, DME, B.Tech, ME, MBA PhD-Malaysia(Automotive), PhD-India (Mechanical)
INTRODUCTION TO ADDITIVE MANUFACTURING

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 APPLICATIONS

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BEAM DEPOSITION

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COMPUTER AIDED PROCESS PLANNING FOR
ADDITIVE MANUFACTURING,

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LIQUID ADDITIVE MANUFACTURING
additive manufacturing technique which deposits
a liquid or high viscosity material (e.g Liquid
Silicone Rubber) onto a build surface to create
an object which then vulcanised using heat to
harden the object

Figure 1: Functional material mix

components can be printed in
one printing process.

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Liquid materials can be used in almost every
phase of a product life cycle, from prototype
construction to mass production. They are
especially suitable for components that
require a combination of functional materials,
and to produce fine components and
structures.

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The liquid materials used for liquid additive
manufacturing may unlock new possibilities for
users, especially when isotropic properties are
needed in the built parts.
The materials used for printing are epoxy resins.
Curing turns the liquid materials into polymers
that are comparable to plastics like polyamide
and PEEK. These materials display high
temperature and media resistance.

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 LIQUID BASED ADDITIVE MANUFACTURING
SYSTEMS
• Building material is in the liquid state.

• The following AM Systems fall into this

category:
1) Stereolithography Apparatus(SLA)
2) PolyJet 3D printing
3) Multijet Printing(MJP)
4) Solid Object Ultravoilet-Laser Printer(SOUP)
5) Rapid Freeze Prototyping

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SHEET LAMINATION IN ADDITIVE MANUFACTURING

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EXAMPLE OF SHEET LAMINATION

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DEVELOPMENT IN SHEET LAMINATION

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DIRECTED ENERGY DEPOSITION

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SHEET LAMINATION
In 1991 a company called Helisys was the first
to introduce sheet lamination technology to
the market. The firm’s laminated object
manufacturing process fused sheets of
material together and used a digitally guided
laser to cut away the desired object (Fig. 1.6).
Though Helisys eventually ended operations
in 2000, other firms have since used
proprietary versions of sheet lamination for
novel manufacturing purposes.

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TYPES OF SHEET LAMINATION
Sheet lamination can be subdivided into groups based on build
material used, such as paper, plastic, metal or woven fibre composites
or forming methods employed, such as CNC milling, laser cutting or aqua
blasting. They can also be categorised further based on the lamination
technique used to bond the sheets together, such as adhesive bonding,
thermal bonding and ultrasonic welding. There are also variations in when
they are formed. In some cases, they are formed and then bonded like
Computer-Aided Manufacturing of Laminated Engineering Materials (CAM-
LEM) process or they are bonded and formed like Ultrasonic Additive
Manufacturing (UAM) process.
Form then Bond process – Sheet material is cut to shape first and then
bonded to the base or previous layer to create a 3D geometry.
Bond then Form Process – In this process as the name suggests sheet
material layers are bonded together before cutting them into the desired
shape

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 CONSIDERING ALL THE ABOVE VARIATIONS, SHEET
LAMINATION CAN BE CATEGORISED INTO THE FOLLOWING
7 TYPES;
• Laminated Object Manufacturing (LOM)
• Selective Lamination Composite Object
Manufacturing (SLCOM)
• Plastic Sheet Lamination (PSL)
• Computer-Aided Manufacturing of Laminated
Engineering Materials (CAM-LEM)
• Selective Deposition Lamination (SDL)
• Composite Based Additive Manufacturing (CBAM)
• Ultrasonic Additive Manufacturing (UAM)

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 HOW SHEET LAMINATION WORKS
Every type of sheet lamination works marginally
different from each other, although the main
principle is the same. A schematic overview is
shown in figure 2 of the original laminated object
manufacturing which was the first
commercialised additive manufacturing
technique in 1991

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SHEET LAMINATION OVERVIEW
(ADDITIVE MANUFACTURING TECHNOLOGIES)

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Sheet lamination technologies use sheets of material to create 3D
objects by stacking them and laminating them using either adhesive or
ultrasonic welding. Once the object is built, the unwanted areas of the
sections are removed layer by layer.

Sheet lamination technology is an umbrella term for Ultrasonic Additive

Manufacturing (UAM, Selective Deposition Lamination (SDL, and
Laminated Object Manufacturing (LOM).

First, a thin sheet of material is fed from the roller or placed onto the build platform.
Depending on the type of sheet lamination, the next layer may or may not be bonded
to the previous sheet. SDL and UAM bond the layers together and then cut the 3D
shape at the end, while CAM-LEM cuts the layers into shape and then bonds the
layers together. This process is continued until it completes all the layers to achieve
the full height. Then the print block is removed, and all the unwanted outer edges are
removed to reveal the printed 3D object.

In sheet lamination, the layer thickness is the same as the thickness of thin sheets of
material and dictates the final quality. Layer thickness also depends on the machine
and process used.

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 SHEET LAMINATION (LOM)
This is an additive-manufacturing process in which sheets of
material are bonded to form an object. Sheet lamination is
a group of processes that create a layer by cutting the
contours of the layer. Laminated object manufacturing
(LOM) (see Fig. 1) does so by stacking plastic sheet
material on top of the sheets below and uses a computer-
controlled cutting device (laser, knife) to cut the lines that
form the edges of the desired shape. When the product has
been printed, the excess material is removed. Paper
lamination technology (PLT) uses especially develop paper
sheets instead of plastic; successive layers are glued to
each other with thermally activated glue

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MATERIAL SUITABILITY

Although sheet lamination can use a wide

variety of materials, such as paper, polymer,
ceramic and metal, each material uses
different binding methods. The most common
sheet lamination material is paper with pre-
applied adhesive where heat and pressure are
used to activate the adhesive layer.

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CBAM PROCESS
SHEET LAMINATION PARTS

Polymers use heat and pressure without the adhesive as it relies on melting the
sheets together. Metal sheets are bound using ultrasonic welding, while materials
such as fibre-based material and ceramic use thermal energy in the form of oven
baking to combine the layers together.

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TYPICAL APPLICATION
Different types of sheet lamination techniques are
used for different purposes and they are directly
tied to the individual process. Paper-based
techniques such as LOM and SDL are used for
full-colour prints while metal-based sheet
lamination is used in hybrid manufacturing.
SLCOM can be used to make production quality
composite fibre parts while the CAM-LEM
process can be used to make ceramic parts.

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HAND MODEL PRINTED USING SDL

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APPLICATION

https://yifeijin.org/sheet-lamination/

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WIRE ADDITIVE MANUFACTURING
The development of wire arc additive manufacturing
(WAAM), now known as directed energy deposition-
arc (DED-arc), is being driven by the need for
increased manufacturing efficiency of engineering
structures. Its ability to produce very near net shape
preforms without the need for complex tooling, moulds
or dies offers potential for significant cost and lead
time reductions, increased material efficiency,
improved component performance and reduction of
inventory and logistics costs by local, on-demand
manufacture.

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First patented in 1920, WAAM is probably the oldest,
outwardly simplest, but least talked about of the range
of additive manufacturing (AM) processes (commonly known
as 3D printing). Using wire as feedstock, the basic process
has been used to perform local repairs on damaged or worn
components, and to manufacture round components and
pressure vessels for decades. However, the advent of high
quality computer aided design and manufacturing
(CAD/CAM) software has made AM in general possible, with
WAAM, in particular, being an area of significant
development. With a resolution of approximately 1mm and
deposition rate between 1 and 10kg/hour or more
(depending on arc source), the operating window of WAAM
is between, and complementary to, highly accurate but
slower laser-based systems and less accurate high-
deposition-rate multi-arc plasma and electron beam
systems.

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WIRE + ARC ADDITIVE MANUFACTURING (WAAM)

The combination of an electric arc as heat source and wire as

feedstock is referred to as WAAM and has been investigated for
AM purposes since the 1990s, although the first patent was filed
in 1925. WAAM hardware currently uses standard, off the shelf
welding equipment: welding power source, torches and wire
feeding systems. Motion can be provided either by robotic systems
or computer numerical controlled gantries. Whenever possible,
MIG is the process of choice: the wire is the consumable electrode,
and its coaxiality with the welding torch results in easier tool path.
MIG is perfect for materials such as aluminium and steel, but
unfortunately, with titanium, this process is affected by arc
wandering. Consequently, tungsten inert gas, or plasma arc
welding, is currently used for titanium deposition.

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 PRINCIPLES OF WIRE ARC ADDITIVE
MANUFACTURING WORK?
WA an arc welding
process to 3D print metal parts.

Unlike the more common metal powder AM processes, WAAM works by melting metal
wire using an electric arc as the heat source.

The process is controlled by a robotic arm and the shape is built upon a substrate
material (a base plate) that the part can be cut from once finished.

The wire, when melted, is extruded in the form of beads on the substrate. As the beads
stick together, they create a layer of metal material. The process is then repeated, layer
by layer until the metal part is completed.

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MATERIALS

WAAM can work with a wide range of metals, provided they are in wire form. This list
includes stainless steel, nickel-based alloys, titanium alloys and aluminium alloys. Any
metal that can be welded can also be used with WAAM.

In terms of material costs, the welding wire used in the WAAM printing process is
significantly less expensive than the metal powder used in metal PBF.

This is because WAAM technology is based on welding, a well-established

manufacturing technology in and of itself. WAAM hardware usually includes off-the-
shelf welding equipment, which is less expensive than many metal 3D printers
available on the market.

Additionally, wire is typically easier to handle than powder, which requires specialised
protective equipment to use

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MATERIALS AND DEPOSIT PROPERTIES
As a generalisation, if a material is available as a welding wire,
it can be used to manufacture parts by WAAM. TWI has
deposited materials including carbon and low alloy steels,
stainless steel, nickel-based alloys, titanium alloys and
aluminium alloys. For many of the materials, the deposit
properties are similar but not exactly those expected from
conventional weld metal in a joint. The notable exceptions to
this are precipitation strengthening aluminium alloys and αβ
titanium alloy Ti-6Al-4V.

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WAAM basics and potential domains of study advancements

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 MATERIALS BEHAVIOUR DURING WAAM
This section presents the behavioural aspects expressed
in terms of the variations of the WAAM process
parameters. This includes heat source, processing
conditions, wire feed, rolling, heating mechanisms, and
other enhancements deployed to optimize the
manufacturing process. Various research groups are
working on different materials to understand the
technical challenges when the materials are subjected
to WAAM process. This section provides valuable
information in terms of perspectives, applications of
advanced tools, interpretations, and standards specific
to the materials approached.
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TYPES OF MATERIAL
Titanium Alloy (Ti-6Al-4V) has been a popular choice for a number of
industrial applications owing to its suitability in the aerospace industry,
which is oriented towards more enhancements for optimum performance.
WAAM with laser as energy source was experimented [46] and it was found
that the globular grain size and column grain width are proportional to
laser beam power and wire feed speed, but inversely proportional to weld
speed, while the epitaxially grown columnar resulting from nucleation in
the microstructure has larger width.
Aluminum Alloy with 1.2 mm thickness. It was noticed that the tensile
properties are obviously influenced by the build direction and the texture
orientation, showing isotropy in the build direction, but anisotropy with
respect to the texture orientation. Because of the weld bead overlapping
that may occur owing to the large molten pool and to the effect of surface
tension, WAAM with a layer width of 7.2 mm cannot be applied for plane
shapes with certain geometrical features.

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INTRODUCATION -WAAM

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WIRE ARC ADDITIVE MANUFACTURING (WAAM)

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METALLIC ADDITIVE MANUFACTURING SYSTEM

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POWDER FEED SYSTEM

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METALLIC ADDITIVE MANUFACTURING SYSTEM

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WAAM OF ALUMINIUM COMPONENTS

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WAAM OF ALUMINIUM COMPONENTS

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APPLICATIONS

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POWDER ADDITIVE MANUFACTURING
Modern production methods, generative manufacturing
processes are part and parcel of industry nowadays.
This requires high quality materials as powder. Our
product portfolio comprises cobalt-chrome alloys,
corrosion resistant alloys, super alloys and special
stainless steels. Super alloys are used in the aerospace
industries, corrosion resistant nickel alloys are used in
the chemical process or consumer goods industries and
cobalt chrome alloys are found in the production of
dental or other medical implants. Our powder materials
are characterized by its purity, reliability and longevity.

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An Important part of AM of metal parts is the initial metarial.
There are different approaches of AM, which use different
types of initial materials, and the most popular technologies,
such as SELECTIVE LASER or ELECTRON BEAM
MELTING, LASER CLADDING and BINDER JETTING, use
initial material in the powdered form, but there are also
technologies which use initial material in sheet or wire form.

The state of art of metal power based on AM will be

presented. It considers THREE main themes- METAL
POWEDERS, PROPERTIES OF METAL POWDERS,
ADDITIVE TECHNOLOGIES, and Properties of metal parts.
It will be shown the methods for mass production of metal
powders for AMT, descriptions on characterization of powder
properties and microstructure and mechanical properties of
metal samples.

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TECHNOLOGIES OF METAL POWDER
Technologies for the production of metal powder conventionally are
separated on base of the following methods:
1. Physical-chemical
2. Mechanical ones

The Physical-chemical methods are associated with physical and

chemical transformations, chemical composition, and structure of
the final (metal power) and significantly differ from raw
materials.
The mechanical methods include various types of milling processes
and jet dispersion melts by high pressure of gas or liquid (also
known as atomization)

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POWDER PRODUCTION
The metal powder is produced in a
standardized process. A vacuum inert
gas atomization plant (VIGA) forms the
core of the powder manufacturing facility.
This plant is made up of a vacuum
induction melting furnace (VIM) and the
atomization unit, which comprises an
atomization zone and powder tower as
well as a cyclone connected to this with a
powder collecting tank. In the plant the
high-purity powder is produced by means
of vacuum induction melting and inert gas
atomization. The individual steps of the
powder production are precisely
coordinated to each other, as they affect
the composition and purity of the powder.
The entire process occurs in vacuum and
inert gas conditions, so as to ensure as
high a purity as possible.

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MECHANICAL-GAS ATOMIZATION

The main process for producing of metal powders for AM.

1. Melting
2. Atomization and
3. Solidifying of the respective metals and alloys

Gas atomizer are usually equipped with a furnace for melting under vacuum or rarely
under protective atmosphere, the feeders of liquid alloy with nozzles in atomizing
chamber, where a thin flow of the melted alloy dispersed on small droplets by high
pressure of inert gas, and the droplets solidify during the flight in atomizing
chamber. Powders produced by gas atomization have a spherical shape, high
cleanliness, and homogeneous microstructure.

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PLASMA ATOMIZATION
It is relatively new process, which was developed for
production of high purity powders or reactive metals and
alloys with high melting point such as titanium, zirconium,
tantalum etc. PLASMA AUTOMIZATION allows to produce
fine particle distribution powders with highly spherical
particles shape and low content or oxygen. The initial
material for PLASMA AUTOMIZATION process is metal wire.

Wire feedstock is fed into a plasma torches that disperse wire

into droplets with subsequent solidification in powder form.
Particle size distribution of powder produced by PLASMA
AUTOMIZATION is 0-200 µm

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 POWDER-BED FUSION PROCESSES
•
subsequently over each other until the desired shape is achieved.
• The power source for powder-bed fusion processes can be laser or electron
beam that melt and fuse metal particles together. Vacuum is required in the case
of electron beam melting (EBM) processes or in case of highly reactive metal
processing (titanium, magnesium, etc.).
• The input powder material is located in the container from which it is fed into
processing zone where it is subsequently fused.
• The powder that is brought to the process zone is in the form of thin layer of
thickness about 0.1 mm. There are various processes assuring even thickness of
powder layers such as roller- or blade-based ones.
• In order to maintain constant distance between the power source and processed
object, the bed is lowered with each new layer.
• The unfused residual powder remains on the powder bed and can be recycled for
further use.

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 POWDER BED FUSION

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BLOWN POWDER PROCESSES
Processes using powder-bed fusion are still limited by
the size of the built table and chamber. A process
known as blown powder (BP) additive manufacturing
can deliver some higher freedom in achieved
geometry of manufactured parts. This method is
available for many years. Its main difference to
currently developed powder-bed methods is there is
no need of powder supply in the form of layer by layer
with subsequent sintering or melting. BP processes
are using an additive material powder that is blown
into the processing zone, where it meets with laser or
plasma beam that melts the particle surface or whole
particles and they are subsequently deposited on the
substrate. The substrate can be present in a kind of
form such as initial component layer, pre-prepared
workpiece, or repaired serviced component. These
principles were applied in many process
developments
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MATERIAL SELECTION
• Powders usually below 50 μm for most powder-bed systems. In this case,
finer powder particles below 10 or 20 μm shall be avoided, as they are
detrimental to the powder flowability.
• Powder between 50 and 100–150 μm for electron beam melting (EBM) and
LMD technologies.
• Porosity content can be evaluated either by SEM observation or by helium
pycnometer. The presence of excessive amounts of large pores or pores
with entrapped gas can negatively affect material properties
The powder morphology can be observed by scanning electron microscope
(SEM). Typical defects to be controlled and minimized are:
1. Irregular powder shapes such as elongated particles.
2. Satellites which are small powder grains stuck on the surface of bigger
grains.
3. Hollow powder particles, with open or closed porosity.

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APPLICATIONS OF PAM
There are basically three main applications of PAM:

1. Laser repair technology (LRT): It is applied in cases when some parts of expensive
constructions are worn or partly broken due to service loadings. The component
replacement would be too expensive in these applications, and thus local repair can
significantly increase the service life and thus safe substantial financial expenses.

2. Laser cladding technology (LCT): Laser cladding technology is in contrary to LRT

applying thinner layers that are mainly reconstructing worn surface, and thus smaller
material volumes are deposited during this process.

3. Laser free-form manufacturing technology (LFMT): Creation of completely new

components is done with the use of laser free-form manufacturing technology. This
technology allows complete buildup of complex-shaped parts—free forms based on
3D computer model. This technology is applicable in prototyping or production of
unique special components. The result of LFMT is almost 100% dense material with
properties comparable with wrought material. Typical minimum wall thicknesses of
free forms are of 1.5 mm

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TRENDS AND FUTURE DIRECTIONS

Postprocessing technologies for additive manufactured parts

Although it is usually referred to additive manufactured parts, they are net shaped; some
postprocessing is necessary in most cases of AM components.

There are two basic reasons for subsequent processing of AM parts: geometry and
properties. During AM processes there is always present partial or complete local
volume melting followed by subsequent rapid cooling due to high metal conductivity of a
large volume of surrounding bulk material in relation to melt size.

These results in many cases in properties that are significantly lower than those
achievable for bulk materials. Therefore, subsequent thermal or thermomechanical
treatment provides significant improvement of mechanical properties. Additionally, it
removes some residual stresses after AM.

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TRENDS AND FUTURE DIRECTIONS

The surface of AM components is generally uneven with visible layers or places where
supporting structures were attached in the course of AM. Geometry itself can be slightly
distorted by thermal stresses present during AM. Therefore, in many cases some
additional processing either from dimensions or surface point of view to be applied to
AM products is necessary.

In cases where surface has some special function (decorative, sliding, etc.), blasting,
grinding, and polishing can be applied for final-state surface achievement. In cases of
high precision parts, machining is unavoidable in order to achieve desired geometrical
tolerances.

The surface after AM can be uneven, and due to thermal stresses during AM, some
small geometry distortions have to be expected.

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