The document provides an overview of foundry processes in mechanical engineering, detailing the steps of metal casting from pattern making to finishing. It discusses common applications, advantages over other manufacturing methods, potential defects and their solutions, and modern alternatives such as 3D printing and investment casting. The conclusion emphasizes the importance of foundries in producing complex metal components and their ongoing relevance in modern manufacturing.

1. PSG COLLEGE OF
TECHNOLOGY
FOUNDRY - PROCESS INVOLVED, APPLICATIONS,
WORTHINESS AND ALTERNATIVES
23E104 – BASICS OF MECHANICAL
ENGINEERING

2. PRESENTED BY
Anish Kumar P S - 24E606
Aathish K – 24E618
Mithun R - 24E629
Shakthi Deepak - 24E643

3. TOPICS COVERED
--> What is foundry?
--> Basic equipments and tools used.
--> Process and practice overview - Mold
preparation, Casting of product
--> Applications in real life
--> Advantages over other processes
--> Demerits – Defects and its solutions,
Modern alternatives
--> Conclusion

4. WHAT IS FOUNDRY?

5. FOUNDRY
A specialized facility that makes metal castings is referred
to as a foundry. Metals are shaped by being melted it into
a liquid, poured into a mold, and then having the mold
material removed once the metal has set and cooled into
desired shapes. It is basically to transform raw metals into
finished products by shaping them through casting. The
two most frequently treated metals are cast iron
and aluminum.

6. Processes:
1)Pattern making
2)Mold preparation
3)Melting and
Pouring
4)Cooling and
Solidification
5)Shakeout and
Cleaning
6)Inspection and
Finishing

8. Typical
work flow in
sand
casting
foundries

9. BASIC EQUIPMENTS AND TOOLS

10. BASIC EQUIPMENTS AND TOOLS
1. SHOVEL
2. HAND RIDDLE
3. RAMMERS
4. STRIKE OFF BAR
5. VENT WIRE
6. TROWELS
7. SLICKS
8. LIFTERS/ CLEANERS
9. DRAW SPIKE

11. BASIC EQUIPMENTS AND TOOLS
10. DRAW SCREW
AND RAPPING
PLATE
11. MALLET
12. SWAB
13. CLAMP
COTTER AND
WEDGE
14. GAGGER
15. BELLOW
16. MOULDING
BOXES OR FLASKS
17. LADLES

12. PROCESS AND PRACTICE OVERVIEW

13. FOUNDRY PROCESS
The typical casting process includes the following steps:
creating a pattern, molding or mold making, melting, pouring,
ejecting, cleaning, finishing and inspecting.
Melting:
The melting process is usually carried out in a furnace. The
furnace is charged with scrap, alloy elements such as
ferroalloys, and raw materials. Metal is "charged" into a melting
boiler, which is then heated over the melting point of the
metal. The molten metal is tapped into a steel pouring ladle
through a spout in the boiler once it has achieved a certain
pouring temperature. The surface of the molten metal is
skimmed to remove any slag or impurities.

14. Degassing:
A technique that is necessary to minimize the amount of
hydrogen in molten metal is called degassing. In metal
castings, gases can develop in one of two ways:
Physically trapped throughout the casting process.
through a chemical reaction within the casting.
If the concentration of hydrogen in the melt is excessive, the
final casting will have numerous pores or holes.
As the metal cools and solidifies, the hydrogen will escape the
molten solution, leaving minute air bubbles. By bubbling
insoluble gas (dry) through the melt by agitation or purging,
hydrogen can be removed from the melt effectively as shown
in the diagram below.

15. Mold Making:
A mold can be understood by taking an example of an ice
tray. The patterns are placed, sand or clay is packed around it
to create a shape, and the pattern is finally removed to make
a shape in the mold. This process is called mold or mold
making.
Molds are expertly crafted with a pattern (a wooden or metal
replica of the thing to be cast), so that the final casting shape
matches the poured mold. Even though silica sand is the most
popular mold material, there are a variety of other materials
that can be utilized, depending on the casting metal and
procedure. Molds can be as little as a few millimetres or as
large as several feet. Single pieces or solid patterns can be
used to create simple designs.

16. Pouring:
In a foundry, molds are filled with molten metal by pouring into
the mold either by gravity, a vacuum, or pressurized gas. Many
modern foundries pour molten metal using robots or automatic
pouring machines. Historically, molds were manually filled with
ladles. The molten metal poured is now allowed to cool inside
the mold until it solidifies.

17. Shakeout and Degating:
The solidified metal component is taken out of the mold. If the
mold is made of sand, this can be done by shaking or turning it.
With the sand still fastened to gates and metal runners through
which the molten metal travels. The shakeout process releases
the casting from the sand.
The process of removing the gates, runners, heads, and risers
from the casting is called degating. A sledgehammer or
specially made knockout machinery can be used to break the
sprue, runners, and gates free from the casting. The gating
system needed to make castings in a mold produces scrap
metal that can be reused as molten metal in the casting
process.

18. Finishing:
Sand or other moulding particles may still adhere to the casting
after degating. Shooting granular particles against the surface
mechanically removes the adhering sand.
To achieve the desired dimensional accuracy, physical shape,
and surface finish, the component undergoes processes like
grinding, machining, and sanding. This makes the final process
of casting. After this, before shipping cast products to
customers, the foundry provides additional services like
painting and assembly. Castings are painted to stop corrosion
and enhance aesthetics.
The processes are carried out by robotic machines which
increases productivity. They also reduce the possibility of
human error and improve the consistency.

19. TYPES OF MOLDING

20. Sand Molds: Made with sand bonded by
clay or chemical binders. Commonly used
for expendable molds.
Metal Molds: Made of steel or cast iron.
Used for repetitive casting in permanent
mold processes.
Graphite Molds: Made from graphite. Ideal
for non-ferrous metals due to thermal
conductivity and lubricating properties.
Based on Material Used

21. Based on Molding techniques
Green Sand Molds
Green sand molds are made using sand, water, and clay. The term
"green" refers to the fact that the sand mold is not baked or cured,
and it retains moisture.
Dry Sand Molds
Dry sand molds are made by baking the sand mould in an oven to
remove moisture. This process enhances the strength and rigidity of
the mold.
Skin-Dried Molds
Skin-dried molds are a hybrid between green and dry sand molds.
The surface of the green sand mould is dried and hardened by
exposure to heat or chemical coatings, while the interior remains
moist

22. CO2 Molds
CO2 molds are created by mixing sand with sodium silicate and
then hardening the mold by passing carbon dioxide gas through it.
The reaction between the CO2 and sodium silicate causes the
sand to harden.
Centrifugal Moulds
Centrifugal casting, molten metal is poured into a rotating mould.
The centrifugal force distributes the metal evenly within the mould
cavity, creating cylindrical castings
Lost Foam Moulds
Lost foam casting involves creating a foam pattern of the desired
shape, which is then coated with refractory material and buried in
sand. Molten metal is poured into the mould, vaporizing the foam
and taking its place.

23. Based on mould design
Open Moulds:
Open moulds are designed for simple shapes and are
characterized by having the top of the mould open to the
environment. This allows for easy pouring of the molten metal.
Closed Moulds:
Closed moulds are used for more complex designs and include
cavities and gating systems to guide the flow of molten metal.
These moulds are fully enclosed, providing better control over the
casting process.

24. APPLICATIONS IN REAL LIFE

25. PRODUCING
METAL
COMPONENTS
FOR INDUSTRIAL
NEEDS SUCH AS
PUMPS, VALVES,
COMPRESSORS,
AND ENGINES.

26. PROVIDING COMPONENTS FOR
ENGINE BLOCKS, TRANSMISSION
PARTS, AND OTHER ESSENTIAL
AUTOMOTIVE PARTS.

27. PRODUCING
METAL TOOLS AND
HARDWARE SUCH
AS WRENCHES,
HAMMERS, AND
PLIERS.

28. PRODUCING POWER
TRANSMISSION SYSTEMS
SUCH AS TURBINES,
GENERATORS, AND
ELECTRIC MOTORS IS ALSO
DONE THROUGH CASTING
IN A FOUNDRY.

29. PRODUCING WEAPONS,
AMMUNITION, AND OTHER
MILITARY EQUIPMENT.

30. WORTHINESS OF FOUNDRY

31. ADVANTAGES OVER OTHER PROCESSES
• Cost-Effective for Large Production
• Versatility in Material
• Produces less material waste
• Produces components with excellent
mechanical properties due to the
controlled solidification process.
• Capable of producing extremely large
and heavy components.
• Ability to Create Complex Shapes
• Suitable for both small-scale, customized
production and large-scale, mass
production.

32. DEMERITS –
DEFECTS AND ITS
SOLUTIONS
Casting defects are imperfections or
irregularities that compromise the quality
specifications of a component. While some
of the defects may be tolerated or
neglected, some casting surface defects
result in weak casting, odd shapes, and
poor functionality. Therefore, they must be
removed or prevented to ensure better
functioning of the end product.
There are various types of casting defects,
but they are generally grouped into four
categories, namely:
Metallurgical defects
Defects due to heat
Mold material defects
Casting shape defects

33. Metallurgical Defects (Metal material)
1)Porosity defects: These are internal die casting defects that are
usually difficult to spot. Forms small holes, voids, or pockets of air
on the metal. Typically, porosities occur whenever air is trapped
in the metal during the casting process. Thus, the resulting
component may have weakened structural resistance.
Gas Porosity: During solidification of the metal, the inability of the
gas to pass through the mold easily leads to the trapping of
bubbles inside the metal.
Shrinkage Porosity: They occur as jagged, angular edges. It is
normal for metals to shrink when then cool and solidify. However,
if the shrinkage cavity is uneven, distorts the shape of the
component, or creates internal holes, it becomes a defect.
Key Solutions: Improve venting, degas molten metal, and reduce
moisture in molds.

34. 2)Sinks: A sink is a press-down impact on the casting surface
that does not precisely copy the mold design. Sinks appear
on the casting surface when there is a sub-surface cavity
present. These depressions occur along thick-walled areas
on the metal surface.
3)Slag Inclusions: A slag inclusion firmly attaches to the
casting, reducing the mechanical characteristics of the final
product. It usually occurs when non-metallic materials cause
irregular crusts on the casting surface. The casting defect is a
ribbon-like entrainment or pocket with sharp edges and
irregular shapes.
Key Solutions: Optimized structural design for the mold, Die
maintenance and improved Gateway.

35. 4)Dross: Dross refers to a metal loss that occurs during
nonferrous metal casting operations. As metal melts, it
oxidizes to form layers of impurities and scum that floats to
the surface of the metal. The impurities occur due to the
mixing of the oxide of the base metal and other metals on
the surface.
5)Soldering: Soldering is a common casting defect during
the casting process. It occurs when molten metal attaches
itself to the surface of the die cavity and stays there after
removing the casting. Consequently, some areas of the
casting parts are either missing material or excess material.
You can identify soldering by visual inspection.
Key Solutions: Decrease the melting time, improve die
quality

36. Defects Due to Heat
1)Hot Tears: Hot tears are some of the significant casting
abnormalities that occur due to heat. This defect occurs
during the solidification of the metal casting. At this stage,
thermally induced tensile strains and stresses develop in
the metal. The hot tear occurs as the metal contracts
when solidifying.
2)Cold Shut: Cold shut defects are cracks that have round
edges. They occur when metal flows into the mold from
more than one point. However, the metal is too cold and
cannot merge properly to form a perfect piece. Thus, a
cold shut occurs as cracks with rounded edges through
the middle of the workpiece, create a weak spot on the
casting.
Key Solutions: Optimize pouring temperature and gating
system design.

37. Mold Material Casting Defects
1)Fusion: Fusion is another sand casting defect that occurs
when sand grains fuse with the flowing liquid metal. This
results in a thin layer of hard, glassy crust firmly attached
to the casting. The main cause of this defect is the low
refractoriness of sand.
2)Swells: Metallostatic forces often cause the mold wall to
move back, causing a swell in the dimensions of the
workpiece. This means that the casting will enlarge
beyond the desired volume, showing as slight, smooth
bulges. As a result, its feeding and machining
requirements will increase and it may lead to metal
wastage.
Key solutions: Enhance the refractoriness of molding
materials. Design molds to withstand molten metal
pressure to prevent the mold wall from moving backward.

38. 3)Metal Penetration: This occurs in situations when the
molten metal penetrates openings or gaps in the molding
sand. The main reason for this is that the grain size of the
molding sand is too coarse, preventing the proper flowing
of the liquid metal. Consequently, you will get a rough
and irregular casting surface, lowering its aesthetics. 4)
4)Drops: These defects happen when the casting is still in
molten form. They are caused when pieces of loose
molding sand or lumps drop from the surface of the cope
into the mold cavity. As a result, an abnormal and
irregularly shaped projection occurs on the casting’s
surface. Drops can also make the metal surface look dirty
and unsuitable for use.
Key solutions: Improved ramming, Using high quality sand

39. Casting Shape Defects
1)Mismatches: Mismatches are casting defects that
occur due to the misalignment of the lower and upper
parts of the mold. It could occur when the cope and
drag of the mold are not properly lined up before
pouring the metal.
2)Flash: Flashes are any excess or unwanted material
that occurs as thin, irregular-shaped occurrences on
the parting line of a die-casting part. Typically, it is a
thin sheet of metal forming on the parting faces and
turning into dross after re-melting. Since flashes often
have larger sizes, they can be seen by visual
inspection.
Key solutions: Proper box pins, regular box, pins
maintanence.

40. MODERN ALTERNATIVES
1. Additive Manufacturing (3D Printing)
Description: Uses layer-by-layer fabrication to create metal parts
directly from digital models.
Advantages: High precision, reduced waste, and elimination of
molds or patterns.
Applications: Prototyping, aerospace components, and intricate
designs.
2. Investment Casting (Lost-Wax Casting)
Description: A wax pattern is coated with refractory material to
form a mold, which is then heated to remove wax before
pouring metal.
Advantages: Superior surface finish and dimensional accuracy
for intricate designs.
Applications: Jewelry, turbine blades, and medical implants.

41. 3. Die Casting
Description: Molten metal is injected into steel
molds under high pressure.
Advantages: High production rate, excellent
surface finish, and tight tolerances.
Applications: Automotive, electronics, and
consumer goods.
4. Continuous Casting
Description: A process where molten metal
solidifies in a continuous mold to produce long
products like billets and slabs.
Advantages: High efficiency, consistent quality,
and reduced waste.
Applications: Steel and non-ferrous metal
industries.

42. 5. Powder Metallurgy
Description: Metal powders are compressed and
sintered to form solid parts.
Advantages: Minimal waste, high material
utilization, and ability to form complex shapes.
Applications: Gears, bearings, and structural
components.
6. Squeeze Casting
Description: Combines casting and forging by
applying pressure during solidification.
Advantages: Strong, high-density parts with
minimal porosity.
Applications: Automotive and heavy machinery
parts.

43. CONCLUSION
Foundry remains a vital manufacturing process, offering unmatched versatility in producing complex
shapes and large metal components. Through advancements in technology and process
improvements, modern foundries address defects and enhance production efficiency.
Foundries play a crucial role in numerous applications, from automotive to aerospace,
demonstrating their indispensable value in real-world manufacturing.
By understanding its processes, benefits, and limitations, industries can leverage the best aspects of
foundry work while embracing innovative alternatives.
"Foundry is not just a process—it's the backbone of innovation in metal manufacturing."

44. THANK YOU
BIBLIOGRAPHY
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H T T P S : / / Y A N T H R I S T . C O M / T O P - 1 8 - F O U N D R Y - T O O L S - E Q U I P M E N T /
H T T P S : / / W W W . R A P I D D I R E C T . C O M / B L O G / 1 7 - T Y P E S - O F - C A S T I N G - D E F E C T S /