Casting Report

8/13/2019 Casting Report

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CASTING REPORT 1

CASTING REPORT

OBJECTIVES

1. To show how the casting process have done.

2. To more know about knowledge of manufacturing process

3. To more understand every step to make sand casting process.

4. To exposes the student about environment in the workshop.

5. To apply a theory that lerned in the class into practical at the workshop.

6. To develop self-learning process among the student.

7. Student will able to learn how to use equipment of casting and machines that are used in

the casting process.



CASTING REPORT 2

INTRODUCTION

Sand casting the most old method in metal casting family. It is produce large component

typically, iron, ore, and etc. usually product of expandable mold is the most roughest surfaces

amongst all. Instead, the material that used for the mold can be used repeatedly.

Basically, sand casting consist of placing a pattern in sand to make an imprint, incorporating a

gating system. Removing the pattern and filing the mold the mold cavity with molten metal,

allowing the metal to cool until it solidifies, breaking away the sand mold and finally removing

the casting.

This casting process is one of the popular casting method because it have many advantage such

as save cost, quick results, high temperature resistance and high melting point resistance.



CASTING REPORT 3

THEORY

The casting process basically involves pouring molten into a mold patterned after part to be

manufactured, allowing it to solidify, and removing the part from the mold.

Important considerations in casting operations are as follows :

Flow of molten metal into the mold cavity

Solidification and cooling of the metal in the mold

Influence of the type of mold material

Casting is a process by fluid melt into a mold, it need to cool in the shape of the form, and then

ejected to make a casting. There are four main elements are required in this process, it is pattern,

mold, cores, and the part. The pattern is original from the mold have been prepared, so the

corresponding cavity in casting in material have been creates. Cores are used to produce tunnels

or holes in the finished mold, and the part is the final output of the process.

A pattern is a replica of the object to be made by the casting process with some modifications.

Some of the modifications that we consider in pattern making process are shrinkage allowance,

parting line, draft, machining allowance and distortion.

Schematic illustration of a typical riser – gated casting. Risers serve as reservoirs, supplying

molten to the casting as it shrinks during solidification.

The casting process is subdivided into two distinct subgroups:

Expandable mold casting

Nonexpendable mold casting



CASTING REPORT 4

Expandable mold casting

Expandable mold casting is classification include sand, plastic, shell and investment of lost-wax

technique moldings. All of these involve the use of temporary and need gravity to help force

molten fluid into casting cavities. In this process the mould is used only once.

Expandable mold casting can be divided into:

Sand casting

Plaster casting (of metals)

Plaster casting (of plastic or concrete)

Shell molding

Investment casting

Permanent mold casting

Its also know as hard-mold casting. Consists of two halves of mold-made from materials with

high resistance to erosion and thermal fatigue such as cast iron, steel, bronze, graphite, refactory

metal alloys.

Vacuum casting

Die casting

Centrifugal casting

Continuous casting.



CASTING REPORT 5

Sand Casting

The traditional method of casting is in sand molds has been used for millennia. Typical

applications of sand casting include machine bases, large turbine impellers, propellers, plumbing

fixtures, and a wide variety of other products and components.

Basically, sand casting consist of placing a pattern (having the shape of the desired casting) in

sand to make an imprint, incorporating a gating system, removing the pattern and filling the

mold cavity with molten metal, allowing the metal cool until it solidifies, breaking away the sand

mold, and removing the casting.

Show the outline of production steps in typical sand casting operation.



CASTING REPORT 6

Sands

There are two general types of sand:

- Naturally bonded (bank sand)

- Synthetic (lake sand)

Types of sand molds

Green sand

- Which is a mixture of sand, clay, and water. The term “green” refers to the fact that

the sand in the mold is moist or damp while the metal is being poured into it. Green-

sand molding is the least expensive method of making molds, and the sand is recycled

easily for subsequent reuse.

Cold-box sand

- In the cold-box process, various organic and inorganic binders are blended into the

sand to bond the grain chemically for greater strength. These molds are

dimensionally accurate than green-sand mold, but more expensive.

No-bake sand

- A synthetic liquid resin is mixed with the sand and the mixture hardens at room

temperature.



CASTING REPORT 7

Patterns

Used to mold the sand mixture into the shape of the casting. It can be in a form of wood,

plastic or metal.

The selection of a pattern material depends on :

-

Size of the casting- Shape of the casting

- Dimensional accuracy

- Quantity of casting required

- Molding process

Type of patterns

One-piece pattern (loose or solid patterns)

Split patterns

Match-plate patterns



CASTING REPORT 8

Cores

Sand cores showing core prints and chaplets to support cores.

Cores are placed in the mold cavity to form the interior surface of the casting and the removed

from the finished part during shakeout and further processing. The cores must strength,

permeability, ability to withstand heat, and collapsibility. Casting with internal cavities or

passages, such as those found in an automotive engine block or valve body, cores are utilized.

The core is anchored by core prints, which are recesses added to the pattern to support the core

and to provide vents for the escape of gases.

“Chaplet” is an additional supports to prevent core from shifting.

Cooling rate

Cooling rate is the rate which casting cools affects its microstructure, quality and

properties. The cooling rate is largely controlled by molding media used for making the

mold.

When the molten metal is poured into the mold, the cooling down begins. This happens

because the heat within the molten metal flows into the relatively cooler parts of the

mold.

Molding materials transfer heat from the casting into the mold at different rates.

For example, some molds made of plaster may transfer heat very slowly, while a mold

made entirely of steel would transfer the heat very fast. This cooling down ends with

solidification where the liquid metal turns to solid metal.

http://en.wikipedia.org/w/index.php?title=Solidification&action=edit

http://en.wikipedia.org/w/index.php?title=Solidification&action=edit



CASTING REPORT 9

Shrinkage

Like nearly all materials, metal is less dense as a liquid than a solid and so a casting shrinks as it

cools, mostly as it solidifies, but also as the temperature of the solid material drops.

Compensation for this natural phenomenon must be considered in two way :

Volumetric shrinkage

- The shrinkage caused by solidification of molten metal can leave cavities in a casting and

weakening it. Risers provide additional material to the casting as it solidifies.

- The riser (sometimes called a "feeder") is designed to solidify later than the part of the

casting to which it is attached. Thus the liquid metal in the riser will flow into the

solidifying casting and feed it until the casting is completely solid.

- In the riser itself there will be a cavity showing the metal which was fed. They are often

necessary to produce parts which are free of internal shrinkage voids

Linear shrinkage

- Shrinkage after solidification can be dealt with by using an oversized pattern designed for

the relevant alloy.

- Pattern makers use special "shrink rulers" to make the patterns used by the foundry to

make castings to the design size required. Using such a ruler during pattern making will

ensure an oversize pattern.

- Thus, the mold is larger also, and when the molten metal solidifies it will shrink and the

casting will be the size required by the design.

Draft

The amount of draft is determined by the size and the shape of the pattern, the depth of

cavity, the method used to withdraw the pattern, the pattern material, the mold material

and the molding procedure. Since draft allowance tend to increase the size of a pattern

and thus the size of a pattern and thus the size and weight of a casting, it is generally

desirable to keep them to the minimum that will permit satisfactory pattern removal.



CASTING REPORT 10

Machining Allowance

When machined surfaces must be provided on castings, it is often necessary to provide

machining allowance on the pattern. This allowance depends to a great extend on the

casting process and the mold material. Ordinary sand castings have rougher surfaces

than those of shell mold castings. We should relate the finishing allowance to the casting

process and also remember that draft may provide or all of the extra metal needed for

machining. If a core is used to form interior cavity, it too must be oversized to

compensate for shrinkage .However if a machining allowance is included, it should be

subtracted from the core dimensions because machining will increase the size of the

hole. If the casting is made directly into metal mold, all of the pattern allowances should

be incorporated into the mold cavity.

Distortion

Some casting shapes still require an additional allowance for distortion. Fro example,

the arms of the U- shaped section may be restrained by the mold, while the base of the U

is free to shrink. This restraint will result the final casting with outwardly sloping arms.

Long, horizontal sections tend to sag in the center unless adequate support is provided

by suitable ribbing. Distortion greatly depends on the particular configuration of the

casting, and we must provide required distortion allowance.



CASTING REPORT 11

Molding box and materi als

A multi-part molding box (known as a casting flask, or referred to as the cope and drag) is

prepared to receive the pattern. For a simple product, flat on the one side, closed at the bottom

and filled with the casting sand. The pattern is placed on the sand and another molding box

segment is added. Additional sand is rammed over and around the pattern. Finally a cover is

placed on the box and it is turned and unlatched, so that the halves of the mold may be parted

and the pattern with its sprue and vent patterns removed.

Chills

If it is desired to have most of the iron or steel casting in a tough, ductile, state but with a few

surfaces hard, it is possible to introduce into the mold, metal plates chills where the metal is to be

hardened. The associated rapid local cooling will form a finer-grained and harder metal at these

locations. The inner diameter of an engine cylinder is made hard by a chilling core.



CASTING REPORT 12

APPARATUS

1) Wooden block

2) Paper

3)

Pencil4) Compass

5) Eraser

6) Ruler

7) Ø 0.3 mm drill

8) Wood chisel

9) Handsaw

10) Sand papers

11) Cope and drag

12) Small and big rammer

13) Small and big downgate

14) Cleaner

15) Casting ladle

16) Shovel

17) Separating agent

18) Sand

19) Casting ladle

20) Variety grades of sand paper or grinder tools

21) Oxyfuel-gas cutting tools or handsaw



CASTING REPORT 13

PROCEDURES

Making the pattern

1. Each group was given a piece of soft wood, a set of chisel, mallet, files, meter rule and a

small saw

2. On the soft wood, students have to draw a layout for the pattern. A layout was drawn on a

piece of paper

3. The sketch was transferred to the soft wood and was cut carefully using small saw as the

wood is soft and might cracked if don’t handle properly



CASTING REPORT 14

4. The pattern then, was shaped by it into desired figure

5. The pattern was smoothen using sand paper and files

6. For locating the pins ,the pattern was drilled

7. Next, the centre of width of the pattern was marked using micrometer high gauge for a

precise centre line

8. Again, the pattern was smoothen using sand paper for smoother surfaces



CASTING REPORT 15

Casting process

1. The manual sand casting was provided to all groups.

2. The pattern was placed at the lower part of the sand casting which is called drag to locatethe suitable position for sprue and riser

3. The pattern was taken out to cover it with parting agent first so that the sand won’t stick

to pattern and process of separating pattern from sand would be easier.

4. Then, the pattern was placed in the drag and filled with sand. The sand was compress to

make it compact and when the drag was rose up, the sand are not spilling down.



CASTING REPORT 16

5. Next, the drag was turn upside down. The other part of pattern was assembled together

with the pattern in the drag and the screws at the side of cope and drag were tightened.

6. The parting agent was added on the pattern and the sand. The sprue and riser were

located at the suitable place.

7. Sand was added and compressed. Then, sprue and riser were removed carefully

8. The screws at the side of the cast was loosened and the cope and drag part were separated

to removed the pattern from the sand carefully so mold remain as it shape.

9. The runner then, was made from mold cavity to the sprue and riser.



CASTING REPORT 17

10. Both cope and drag part were assembled together and the screws were tightened neatly.

11. After that, molten metal in the furnace was poured continuously through the sprue until

the molten metal appeared at the riser.

12. The metal was left to cool. The equipment for finishing already taken out.

13. Then, the alloy cast was taken out and cleaned using steel brush.

14. The gating system was cut by using saw.

15. The alloy cast was smoothen using sand paper for finishing.



CASTING REPORT 18

DATA AND RESULTS



CASTING REPORT 19

DISCUSSION

Safety Precautions

1. Students must wear proper attire when entering the workshop. Attire must be neat, tidy

and protective

2. Students must wear gloves and other protective gear when carrying out projects in the

workshop.

3. Students are prohibited to play around, eat, drink or smoke in the workshop.

4. Never use tools and apparatus without permission.

5. Never use any damaged or malfunctioned tools, apparatus and materials.

6. Use the proper tools for every task.

7. Students must obey instructor’s instructions.

8. It is advisable not to wear gloves while using the electric drill as student may not grip the

electric drill well.

9. When using chisel and hammer, it must be done on the anvil.

When designing the shape of the project, we must avoid design the shape that has the small gap

since it will causing the difficulty when removing the shape from the sand. The design of the

shape should not be too thin to prevent it from broken when sawing it into two parts. When

melting the metal with furnace, extra precaution must be taken since the high melting



CASTING REPORT 20

temperature of the molten metal can cause the injuring to the user. During the process placing the

desired casting in sand, tamping the sand compact to prevent it from crush when remove the

shape from the sand. Try to brush the designing shape as smooth as possible so it will not stick

with the sand. The distance of the risers pouring basin cannot be too near with the shape so there

are space for tamping the sand. The process of pouring the molten metal into the mold must be

proceed in one shot without delaying in order to prevent molten metal solidified halfway and

block the passage.

CONCLUSION

Sand casting has existed for centuries. While the basic process has changed little over time, it

continues to be the most popular method for metal part production. Its popularity is due, in part,

to the wide range of part sizes that can be cast and the broad selection of metal alloys that can be

processed. Another factor is that sand casting is a faster and less expensive process than die

casting or investment casting.

The process derives its name from the use of sand to create the molds into which molten metal is

cast. The molds are created by packing sand around a pattern. The sand holds its shape with the

addition of clay and water (green sand) or a chemical binder (dry sand). After the sand has been

packed, the pattern is removed, and metal is poured into the cavity in the sand mold. Once

cooled, the sand is broken away from the cast metal part.

For sand casting, the most common metals are iron, steel, bronze, brass and aluminium. With

these alloys, sand casting can produce small parts that weigh less than one pound or large parts

that weight several tons. The process is used to make medium to large parts such as valve bodies,

plumbing fixtures, locomotive components and construction machinery. Its versatility also

allows sand casting to produce small parts such as buckles, handles, knobs and hinges. It is a cost

effective and efficient process for small lot production, and yet, when using automated

equipment, it is an effective manufacturing process for high-volume production.



CASTING REPORT 21

REFERENCE

1. en.wikipideia.org/wiki/Sand_casting

2. www.sandcasting.bizhosting.com

3. EN. MASJURI BIN MUSA @ OTHMAN : Lecture Notes Manufacturing Process

BMFG 2323 - Metal Casting & Equipment

4. E. PAUL DEGARMO, J.T. BLACK A. KOHSER: Materials and Processing In

Manufacturing, Prentice- Hall India, 8th Edition. 2002

5. Engineering.blogspot.com/search/label/Casting%20defects

6. www.custompartnet.com/wu/SandCasting

7. www.efunda.com/processes/metalprocessing/sand_casting_intro.cfm.

http://www.sandcasting.bizhosting.com/


http://www.custompartnet.com/wu/SandCasting


http://www.efunda.com/processes/metalprocessing/sand_casting_intro.cfm





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