arslan sand casting

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Submitted to : Dr. Nasir Rehman JadoonSubmitted by: Muhammad Arslan

Sand Casting

Mechanical Lab. Report

Muhammad Awais

Muhammad Owais


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Contents:

1. Abstract 3

2. Apparatus

2.1.Equipment Used . 3

2.2.Material Used .. 3

3. Introduction . 5

4. Procedure

4.1.Preparation of green sand 6

4.2.Preparation of mold . 7

4.3.

Pouring of metal . 9

5. Discussion . 10


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1.Abstract:

The purpose of doing this experiment is to understand the process of sand casting. Understanding of

procedure and which equipmentsare used, the possible defects in the job due to sand casting and

how can they be removedin this casting was the main objective. This experiment has two parts, the

very first is molding and the second is pouring. We made a part from aluminum in this experiment.

2.Apparatus:

2.1.

Equipment used:

i. Drag

ii. Cope

iii. Ladle

iv.

Cruciblev.

Rammer

vi. Pliers

vii. Sieve

viii. Pattern

ix. Trowel

x. Brush

2.2.Material used:

i. Sand

ii.

Molasses

iii. Water

iv. Aluminum

v. Parting agent


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Tools Used:

Fig 01 Fig 02

Pattern Used:

Fig 03 Fig 04


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3. Introduction:

Sand casting, also known as sand-mold casting and the most widely used casting process,

utilizes expendable sand molds to form complex metal parts that can be made of nearly any

alloy. Because the sand mold must be destroyed in order to remove the part sand casting

typically has a low production rate. The sand casting process involves the use of a furnace,metal, pattern, and sand mold. The metal is melted in the furnace and then ladled and poured

into the cavity of the sand mold, which is formed by the pattern. The sand mold separates along

a parting line and the solidified casting can be removed. Sand casting is used to produce a wide

variety of metal components with complex geometries. These parts can vary greatly in size and

weight, ranging from a couple ounces to several tons. Some smaller sand cast parts include

components as gears, pulleys, crankshafts, connecting rods, and propellers. Larger applications

include housings for large equipment and heavy machine bases. Sand casting is also common in

producing automobile components, such as engine blocks, engine manifolds, cylinder heads,

and transmission cases. Pictures of some of the parts manufactured with sand casting areshown below.

Fig 05 Fig 06


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4. Procedure:

There are seven steps in this process:

i. Preparation of Green sand.

ii. Place apattern in sand to create a mold.

iii.

Incorporate the pattern and sand in a gating system.

iv. Removal of pattern.

v. Fill the mold cavity with molten metal.

vi. Allow the metal to cool.

vii. Break away the sand mold and remove the casting.

4.1.

Preparation of Green sand:

i. First of all sand was prepared. The required amount of sand was sieved firstly using

coarse sieve and then fine sieve.

ii.

This sieved sand is then mixed with water and molasses in following quantities,

Sand: 70% (by weight)

Water: 2% (by weight)

Molasses: 28% (by weight)

iii. For the removal of the moisture present in green

sand the mixture was spread out on plastic sheets

under the sun as shown in Fig 07.

iv.

The consistency of the sand was checked at regular

intervals to make sure it didn't dry out completely.

The test for checking the consistency of the sand is

to hold the sand in one hand and if the sand

doesnt stick with hand instead sticks with the

other particles of the sand; the sand is ready for

the mold preparation.

Fig 07
http://en.wikipedia.org/wiki/Pattern_%28casting%29http://en.wikipedia.org/wiki/Pattern_%28casting%29


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4.2.

Placing of the pattern in sand:

i. Parting agent was dusted on the wooden block so that sand cant stick with the

block.

ii. The drag, a lower part of the metallic container for the mold, was placed face down

on a wooden block.

iii.

Lower part of the pattern was placed face down in the center of drag.iv.

Parting agent was dusted on the pattern so that sand cant stick with the pattern.

Parting agent is talcum powder or crushed lime stone as they are hydrophobic in

nature and cant absorb the moisture present in the sand.

v. Drag was filled with sand using fine sieve.

vi. For maximum amount of sand to be filled in the drag, the sand in the drag was

compressed using reamers and hammers.

vii. Vacant spaces produced, after compression, were filled with sand.

viii. Using reamer the surface of the sand was made smooth and aligned with the walls

of the drag.

ix.

Parting agent was dusted on the surface of the sand so that not to stick with thewooden block when inverted.

x. For the upper part of the mold the cope was placed on the drag.

xi. Upper part of the pattern was placed face down on the in the center of the cope.

xii. Cope was allowed to fill with sand using fine sieve.

xiii. For maximum amount of sand to be filled in the cope, the sand in the cope was

compressed using reamers and hammers.

xiv. Vacant spaces produced, after compression, were filled with sand.

xv. Using reamer the surface of the sand was made smooth and aligned with the walls

of the cope.

xvi. Sand in the drag and cope were allowed to stick the walls.

xvii.

The patterns were removed very carefully so that not to affect the imprints made on

the sand in drag and cope respectively.

xviii. Runners and risers were cut on the cope for metal pouring.

xix. Air vents were made on the cope so that when pouring will be done gases may

escape through those vents.

xx. Drag and cope were then left under sun for 3-4 hours to dry off completely.

xxi. Open and closed molds are shown in fig 08, 09, 10 & 11.


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Fig 08 Fig 09

Fig 10 Fig 11


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4.3.

Pouring of metal:

i. Crucible was placed in the furnace. Furnace was made of fire bricks and fire clay

whereas the crucible was made of graphite.

ii. On the basis of calculations, 2.5 kg Aluminium was placed in the crucible and heating

was done.

iii.

At first heating was done using only methane to prevent the cracks that mayproduce due to the thermal expansions.

iv. Then a lid is placed on the furnace and air was blown so that temperature inside the

furnace may rise to 800C. Lid contained a hole in centre so that gases produced in

the melting of Aluminium may escape.

v. Aluminium metal was allowed to melt in the furnace.

vi. After the melting process, the crucible was taken out with the help of pliers and

placed in the ladle.

vii. Molten metal was poured into the sprue and continued until the metal appeared

through riser.

viii.

Metal was allowed to cool down and solidify then the sand was removed usinghammers and pliers. Figure shows the part manufactured.

Fig 12 Fig 13


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Fig 14

5.

Discussion:

When the manufactured part was inspected some defects were observed. The upper

surface of the job contained vertical columns of material. These columns might be because

of greater cross section of the air vents made in the mold for the removal of gases,

produced during pouring. This greater cross section not only allowed gases to escape but

also materials flow. It was noted that the center of the top surface of job was not exactly

shaped like mold. It was due to the shrinkage effect of material after solidifying. Less molten

metal than required was poured. We stopped filling material when mold was completely

filled with molten metal. Now as the material solidified shrinkage in job happened and jobs

volume reduced resulting in reduction of height in center of top surface of job. This can be

reduced by adding fluid more than the required volume of job. Another fault noted was the

roughness of the surfaces of the job. The grain size was not fine enough to create

smoothness on the surfaces. For this purpose graphite fine grained powder can be poured

on the surface.

The final object can now be machined to make its surfaces smoother. Gears can be cut

on it and also it can be used as a pulley.

arslan sand casting

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