The process of Casting. how it is different from other manufacturing processes

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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:-
  1. 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.
  2. The pattern will be placed between the two parts of sand (assuming sand casting method).
  3. While placing the pattern, the gating system, riser, runner will be provided in the system.
  4. When the sand will occupy the shape of the pattern, the pattern will be ejected from the sand and the cavity will be obtained.
  5. After that the hot liquid metal is poured into the cavity.
  6. After the cooling and solidification, the object will be ejected by braking the sand mould.

ADVANTAGES:-
  1. Many complex shapes that can’t be obtained by any other manufacturing process are produced by casting.
  2. Casting is preferred for higher accuracy, If the mould is prepared correctly and appropriate casting methods are used.
  3. It has the advantage of low cost requirement.
  4. The material wastage is controlled as compared to other processes like machining, welding etc.
  5. By the adjustment of cooling or solidification time the required grain structure can be obtained in the material.
  6. As it eliminates the wastage of material, it also provide the advantage of light weight component production.
  7. 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:-
  1. There are many casting defects that can occur while using the process.
  2. Skilled labour is required for better operation and to avoid the casting defects.
  3. In some casting process like sand casting, there is an issue of poor surface finish and dimensional accuracy.
  4. Due to poor surface finish in sand casting, there will be the need of further process like grinding, lapping etc.
  5. It needs the calculation of various allowances correctly before the operation. This analysis makes it time taking process for job production.
  6. There is a problem of brittleness with the part manufactured by casting methods.



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