FACULTY OF ENGINEERING, TECHNOLOGY, APPLIED
DESIGN AND FINE ART
DEPARTMENT OF MECHANICAL ENGINEERING
A PRACTICAL REPORT ON THE PREPARATION OF A WOODEN
PATTERN FOR SAND CASTING OF AN ENGINE BLOCK
BY
GROUP II (MEC II)
S/ NAME OF REGISTRATION
NO STUDENTS NUMBER
1 ENDREONZI 2022/A/KME/0455/F
GILBERT
2 OPIYO MARVIN 2022/A/KME/0958/
G/F
3 TUMUSIIME 2022/A/KME/1703/F
SAMUEL
4 AGABA TYSON 2022/A/KME/0961/
G/F
5 SALIM SALEH 2022/A/KME/0940/
G/F
6 RUKUNDO 2022/A/KME/1320/F
TIMOTHY
7 ODONG JAMES 2022/A/KME/0959/
G/F
8 OYESIGYE 2022/A/KME/0458/F
COLLINS
pg. i
9 ARINAITWE 2022/A/KME/0957/
ROGGERS G/F
10 OKECH ESAU 2022/A/KME/0962/
FELIX G/F
11 MASEREKA 2021/A/KME/2037/F
RODRICK
A REPORT SUBMITTED TO KABALE UNIVERSITY, DEPARTMENT OF
MECHANICAL ENGINEERING IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE AWARD OF THE DEGREE OF BACHELOR OF SCIENCE IN MECHANICAL
ENGINEERING OF KABALE UNIVERSITY.
APPROVAL
This industrial training report was submitted to Kabale University,
Department of Mechanical Engineering after the approval of the following:
MR. ROBERT SEKAJJA KAKEBE
LECTURER, FOUNDRY TECHNOLOGY
KABALE UNIVERSITY
Signature: Date:
MR. BRUNO BERENTI
PRACTICAL SUPERVISOR
KABALE UNIVERSITY
Signature: Date:
pg. ii
ACKNOWLEDGEMENT
First and foremost, we express our sincere gratitude to God for His
unconditional love, guidance and protection; and for making the project a
success. It is entirely by His grace that we have reached this far in life in
general and the academic journey in particular. Praise, glory and honor be to
Him!
Special thanks also go to the Mechanical Engineering Department of Kabale
University especially our lecturer Mr.Robert Kakebe and Mr. Berenti Bruno for
their constant advice and guidance regarding the project as well as availing
us with this study time so as to apply the theoretical skills learnt in class into
real life problem-solving situations and understanding of the Mechanical
Engineering profession at large.
pg. iii
ABSTRACT
The purpose of this report is to investigate the concept of wooden patterns
especially engine block pattern and their potential applications in the
automotive industry.
Pattern refers to a replica or model used to create the mold into which
molten metal or other materials are poured to form a specific shape. It is an
integral part of the casting process and plays a crucial role in determining
the final shape and dimension of the desired shape.
Engine block patterns are essential tools used in the manufacturing of engine
blocks, as they serve as a template for creating the molds necessary for
casting the engine block.
To gather the necessary information for this report, extensive research was
conducted through academic journals, industry publications, and online
resources.
pg. iv
Table of Contents
APPROVAL....................................................................................................................................................ii
ACKNOWLEDGEMENT.................................................................................................................................iii
ABSTRACT...................................................................................................................................................iv
WOODEN ENGINE BLOCK PATTERN PROJECT...............................................................................................1
1.0 : Title of the project...........................................................................................................................1
1.2 : Objective of the project...................................................................................................................1
1.3: Introduction......................................................................................................................................1
1.4 : Theory of the project.......................................................................................................................2
1.4.1: Type of Pattern chosen..............................................................................................................2
1.4.2: Reason for choosing the type of pattern....................................................................................2
1.5: Tools and Equipment........................................................................................................................3
1.5.1: Pictures of some of the basic tools and equipment used..........................................................3
PROCEDURES FOLLOWED TO MAKE THE PATTERN......................................................................................4
2.1 : Design and Measurements..............................................................................................................4
2.2: Pattern Material Selection................................................................................................................4
2.2.1: Advantages of using wood as a material for making pattern.....................................................4
2.2.2: Limitations of wood as a pattern making material.....................................................................5
2.3 : Pattern Layout..................................................................................................................................5
2.3.1: Isometric View and original view of the pattern........................................................................5
2.4 : Rough Stock Preparation..................................................................................................................6
2.5 : Rough Shaping.................................................................................................................................6
2.6 : Refining Block Pattern......................................................................................................................6
2.7 : Surface Smoothing...........................................................................................................................6
2.8 : Sealing and Finishing........................................................................................................................6
2.9 : Final Inspection................................................................................................................................6
2.10: Views of the Final Pattern...............................................................................................................7
3.0: COLOR CODING.....................................................................................................................................8
3.1: Pattern Color Coding.........................................................................................................................8
4.0: CHALLENGES FACED DURING THE PROJECT..........................................................................................9
5.0: CONCLUSION......................................................................................................................................10
6.0: REFERENCES.......................................................................................................................................11
pg. v
pg. vi
WOODEN ENGINE BLOCK PATTERN PROJECT
1.0 : Title of the project
The pattern of a wooden engine block with a single cylinder.
1.2 : Objective of the project
To make a small engine block of at least one cylinder for either
motorcycle, compressor or water pump.
To cater for the allowances such as machining allowances, taper and
finishing allowances.
1.3: Introduction
The engine block is an integral component of an internal combustion engine,
functioning as the main structural support for various engine components
and providing the essential framework for power generation.
Traditionally, engine blocks have been manufactured using cast iron or
aluminum due to their exceptional mechanical properties and heat
dissipation capabilities. However, recent advancement has opened up new
possibilities including utilization of wood as a material for making engine
block pattern.
This report aims to delve into the concept of using wood as an engine block
pattern, which serves as the prototype for creating molds used in the casting
process. By examining the advantages, limitations, manufacturing
techniques of wooden engine block patterns, this report sheds light on the
potential benefits and challenges associated with this innovative approach.
pg. 1
1.4 : Theory of the project
A wooden engine block pattern is a prototype of an engine block made of
wood. The pattern is used to make sand casting molds that will be used in
casting the engine block.
Wooden engine block patterns are an alternative to traditional patterns made
of metals such as iron or aluminum. Wooden patterns offer several
advantages such as reduced weight, lower cost, and superior thermal
insulation compared to metallic patterns.
The selection of wood material for engine block patterns is critical. The
strength, stability, and durability of the pattern depend on the wood species,
wood moisture content, and how the wood was processed.
In other words, to prepare a wooden pattern for sand casting an engine block
of a known dimension, there are several considerations in terms of material
selection.
1.4.1: Type of Pattern chosen
We chose two-piece or split pattern; a two piece or split pattern is a type of
pattern where the mold is created using two separate pieces of wood that
are joined together. The pattern consists of two halves, typically with a
parting line running through the middle.
1.4.2: Reason for choosing the type of pattern
The reason for choosing a particular type of pattern depends on several
factors and considerations;
Firstly, a two-piece pattern allows for complex designs and intricate details to
be incorporated into the pattern. The separate halves of the pattern can be
individually carved and shaped to accurately reflect the features and
dimensions of the engine block design. This level of intricacy may not be
achievable with a single piece pattern.
Secondly, a two-piece pattern can facilitate the creation of core prints, which
are recessed areas on the pattern that create space for the insertion of sand
cores during the casting process. Sand cores are used to create internal
passages and features in the engine block that cannot be achieved solely
through the mold cavity. Th presence of core prints in a two-piece pattern
allows for accurate placement and support of the sand cores, resulting in
precise internal features within the engine block.
Lastly, a two-piece pattern allows for easy handling and manipulation during
the mold-making process. The pattern can be divided into halves, making it
pg. 2
easier to lift, position, and align within the molding flasks. This can reduce
the chances of misalignment or damage to the pattern during the mold
preparation.
1.5: Tools and Equipment
Sand Paper
Wood
Saw
Planer
Measuring tools like calipers, compasses and protractors
Chisels
Sand molding tools like lathes, milling machines and grinders
1.5.1: Pictures of some of the basic tools and equipment used
pg. 3
PROCEDURES FOLLOWED TO MAKE THE PATTERN
2.1 : Design and Measurements
We began by obtaining the design specifications and measurements for the
engine block pattern. This involved taking direct measurements on the
original engine block from the workshop.
We also accounted for the allowances during measurements. Allowances are
the additional dimensions added to the pattern to account for the shrinkage
of the molten metal as it cools and solidifies and are as follows:
o Shrinkage allowances; the shrinkage allowance compensates for the
reduction in size that occurs as the molten metal cools and solidifies.
This allowance as per the pattern made was calculated as
1
¿ inch per foot of casting thickness
8
o Finish allowance; the machining or finishing allowance is an additional
material to the pattern to allow for post-casting operations such as
machining, grinding, or polishing. The specific allowance depends on
the required surface finish and machining operations to be performed
1 1
and can be calculated as ¿ ¿ inch per surface
32 16
o Draft angle; the draft angle is the taper added to the vertical surfaces
of the pattern to facilitate its removal from the mold. This angle allows
for easy release of the pattern without damaging the mold or the
casting and can range from 1 to 3 degrees.
2.2: Pattern Material Selection
We chose suitable material for the pattern that can withstand the production
process and accurately reproduce the desired shape.
We used a suitable wood species for the pattern, considering factors such as
stability, strength, availability, and affordability. The common option we had
for the wood specie was mahogany. We also ensured the wood was of good
quality and properly dried to prevent warping or cracking.
pg. 4
2.2.1: Advantages of using wood as a material for making pattern
Wood can be easily worked.
It is light in weight.
It is readily available.
It is relatively cheap.
It is easy to join.
It is easy to obtain a good surface finish.
Wooden laminated patterns are strong.
It can be easily repaired
2.2.2: Limitations of wood as a pattern making material
It is susceptible to moisture.
It tends to warp.
It wears out quickly due to sand abrasion.
It is weaker than metallic patterns.
2.3 : Pattern Layout
Based on the design and measurements, we created a layout or template on
paper to visualize the overall shape and dimensions of the pattern.
2.3.1: Isometric View and original view of the pattern
pg. 5
2.4 : Rough Stock Preparation
We obtained a suitable wooden block or plank larger than the dimensions of
the pattern.
We cut and shaped it to an approximate dimension, leaving extra material
for refining at a later stage.
2.5 : Rough Shaping
We later began shaping the rough stock using woodworking tools such as
saws, chisels, or carving knives.
This was to remove excess material to achieve a rough outline of the engine
block pattern.
2.6 : Refining Block Pattern
During this stage, we used hand tools and some power tools like routers, files
or sanders to refine the shape of the pattern.
We ensured precise measurements and smooth surfaces, paying attention to
details such as fillets, grooves and openings to obtain a required shape.
2.7 : Surface Smoothing
Here, we progressively sand the pattern to achieve a smooth and polished
surface.
We started with coarse-grit sandpaper and gradually moved to finer-grit sand
paper until the desired level of smoothness was attained.
2.8 : Sealing and Finishing
During this stage, we applied wood sealer or finish to protect the pattern
from moisture absorption and enhance its durability.
This step involved using a clear coat, paint or any other suitable finish,
depending on the group preference.
pg. 6
2.9 : Final Inspection
This stage involved all the group members carefully inspecting the pattern
ensuring its dimensions, features, and surface finish meet the required
specifications. We also made the necessary adjustments needed.
2.10: Views of the Final Pattern
pg. 7
3.0: COLOR CODING
Color coding is a common practice in various industries, including
manufacturing and construction. It involves assigning specific colors to
patterns to indicate certain characteristics or properties.
Patterns are imparted colors and shades in order to;
Identify quickly the main body of the pattern
Identify core prints, loose piece and others
Visualize the surface to be machined
As per the American pattern color scheme;
Black – cast surface to be un machined
Red – cast surface to be machined
Red strips on yellow base – loose piece and seating
Yellow – core print seats
Black strips on yellow background – stop offs or support
No color – parting surfaces
3.1: Pattern Color Coding
pg. 8
4.0: CHALLENGES FACED DURING THE PROJECT
The cost of hiring some equipment from outside workshops for example hand
tool equipment and some power equipment as well
Accidents in terms of cuts while using sharp equipment in shaping the
grooves and drilling the holes into the wood to make the shapes.
It also took us a lot of time gathering the equipment to use and the distance
moved in search for the equipment was also tiresome.
Complexity in the design; as per the assignment, it was generally complex to
analyze and come up with a proper and clear layout. This took us some
period of time trying to analyze and also more cost incurred in the process.
Language barrier especially where we faced hard times in communicating
with some other technicians whom we needed to consult for some
equipment.
Lastly, there was rampant interruption of the work due to bad weather
especially rain.
pg. 9
5.0: CONCLUSION
In conclusion, a wooden engine block pattern is an alternative prototype for
engine blocks. The selection of the wood species, manufacturing techniques,
and finishing is critical for the pattern’s durability, stability, and accuracy.
Wooden patterns offer several advantages including lower cost, reduced
weight, and superior thermal insulation. however., wooden patterns may not
be suitable for high-performance and heavy-duty engines due to their limited
structural strength.
pg. 10
6.0: REFERENCES
Foundry technology by P R
Principles of metal casting by Heine
Principles of solidification by B Chalmers
Foundry technology by K P Sinha and D B Goel
Lecture notes by Mr. Robert Kakebe
pg. 11
