Question

Which casting process is the most suitable for a small number of high quality parts for an expensive sports car? (3 marks) (a) (b) Which casting process is the most suitable for a small number of low quality parts for a 'one-off prototype? (3 marks) (c) On the basis of cost, choose between sand casting and lost wax casting: 1) for a small number of parts, (3 marks) and (ii) for a large number of parts (3 marks): (d) Why is the rate of cooling important in metal casting? (3 marks) (e) What sets the upper limit on pouring speed in metal casting? (2 marks) (0 What might happen if the pouring speed was excessive? (3 marks)

Answer 1

(a) Investment casting process is most suitable for a small number of high quality parts for an expensive sports car because it has good surface finish & complex shape of patter can be made easily. (b) sand casting process is the most suitable for small number of low quality parts for a one off prototype. (c) on the basis of cost (i) for a small number of parts for low cost of manufacturing, sand casting is most suitable because pattern can be made easily and takes loss manufacturing time. (ii) for a large number of parts for low cost of manufacturing cost ware casting is most suitable because more number of parts can be attached to gating elements pattern assembly, by which production time is received which is proportional to cost. (d) the rate of cooling important in metal casting because higher the cooling rate of surface of the casting in content with the mould, the smaller the grain size higher