manufacturing on commercial scales. The process has greatly evolved on its various aspects through the efforts by researchers over last 50 years. The materials and machines used have significantly improved over last few decades adding the versatility of the process and overcoming some of the limitations. However the process still is the most time consuming in the entire production line up. The main implications of the time constraints of this process are to ensure quality castings.

A typical 10 hours burnout cycle is designed to suit the curing requirements of investment powder and burning-out requirements of wax and wax residues. Although the powder mold cures over the entire length of burnout cycle, most of the curing is due to rise in temperature. The hold times are specifically designed to ensure thorough burnout of wax and its byproducts. (Ref. 2, 3).

The other aspect is the time consumed in repairing different problems resulting from the inadequacies of lost wax investment and particularly casting processes. It was observed that about 90% of the problems leading repairing or rejections have their origin in the casting. When it comes to casting, the flowing and filling properties of molten metal are crucial (Ref.1, 4, 6). The flow of metal at the time of casting is governed by following factors: -

1. 1.Permeability of the powder mold,
   2.Flask temperature and metal temperature
   3.Viscosity of the gas
   4.Pressure difference between inside and outside of the flask.
   5.Wall thickness of the powder mold.

The effective control over these factors by traditional method has its own limitations and it is difficult to maintain them at optimum levels every time we cast. Hence some innovative approach was necessary to assure the consistency in the casting quality. The
 

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