Casting
- Sand casting is the most basic method of casting.
- Casting is one of the most used manufacturing process in the field of production in all over the world.
- It is an old manufacturing art.
- In this process the metal is brought into the molten state and then poured in a mould.
- The mould will have the shape of desired part
- Complex shapes can be achieved in economical way.
- The material will be poured in the mould cavity to produce a part.
- Then the molten material will be allowed to solidify and desired product will be produced.
- Several types of materials can be used for casting e.g. molten metal, epoxy resin, plastic etc.
PROCESS:-
- First of all, a basic thing ‘pattern’ is required to obtain the mould cavity. Pattern will have the shape of desired product and it would have the required allowances to get the dimensional accuracy.
- The pattern will be placed between the two parts of sand (assuming sand casting method).
- While placing the pattern, the gating system, riser, runner will be provided in the system.
- When the sand will occupy the shape of the pattern, the pattern will be ejected from the sand and the cavity will be obtained.
- After that the hot liquid metal is poured into the cavity.
- After the cooling and solidification, the object will be ejected by braking the sand mould.
ADVANTAGES:-
- Many complex shapes that can’t be obtained by any other manufacturing process are produced by casting.
- Casting is preferred for higher accuracy, If the mould is prepared correctly and appropriate casting methods are used.
- It has the advantage of low cost requirement.
- The material wastage is controlled as compared to other processes like machining, welding etc.
- By the adjustment of cooling or solidification time the required grain structure can be obtained in the material.
- As it eliminates the wastage of material, it also provide the advantage of light weight component production.
- The range of size of the component to be casted is from very small (5-10) gm. To very heavy component (2.5x10⁵ kg.). This large range is very essential feature of casting method which makes it a unique manufacturing process.
DISADVANTAGE:-
- There are many casting defects that can occur while using the process.
- Skilled labour is required for better operation and to avoid the casting defects.
- In some casting process like sand casting, there is an issue of poor surface finish and dimensional accuracy.
- Due to poor surface finish in sand casting, there will be the need of further process like grinding, lapping etc.
- It needs the calculation of various allowances correctly before the operation. This analysis makes it time taking process for job production.
- There is a problem of brittleness with the part manufactured by casting methods.
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