Shell moulding, also known as shell mould casting, is a process of expendable mold casting using resin-covered sand to form the mold. This process has better dimensional accuracy, a higher rate of productivity, and lower labor requirements compared to sand casting. Let us have a deep insight into the pros and cons of shell mould casting in this article.
Advantages of shell mould casting :
- More dimensional accuracy than sand castings.
- Tolerance of +0.25 to -0.25 mm for steel casting and +0.35 to -0.35 mm for grey cast iron is obtained.
- The surface should be smooth in shell mould casting. range of roughness is 3 to 6 microns.
- A very small amount of sand needs to be used.
- Mechanization is readily possible because of the simple processing involved in shell moulding.
- No gas inclusion occurs because of permeability of shell is high.
- Less foundry space required for the mould casting process.
Disadvantages of shell mould casting :
- Economical only if used in large production.
- The size of the casting obtained by shell moulding is limited.
- The highly complicated shape can not be obtained.
- More sophisticated equipment is needed for handling the shell mouldings.
- High pattern cost so the production cost is also high.