DESIGN AND FABRICATION OF INVESTMENT CASTINGS PROCESS SET-UP AND TO INVESTIGATE FACTORS AFFECTING THE CASTINGS

Abstract

There are number of advantages that have been claimed for Investment Casting Process in comparison to ordinary sand casting process. It is an il-process for achieving desired dimensional accuracy as no ra✓pping allowance has to be given, thus eliminating machining which is very difficult, if not impossible especially for esoteric metals. Although the process was put to industrial applications in early fifties, their use was limited to artistic value only. In this investigation low cost facilities required for the process have been designed and suggested which are useful at laboratory level. Indigenous materials are used for making the wax patterns. On lend has been found out to be best out of three blends used. This blend consists of -25% Bees wax, -30% Ceresin wax, 45% Montan wax (Black). Four types of binders viz., ethyl silicate, plaster of paris, clay and sodium silicate have been investigated at different levels of concentration and their effect on castings has been studied, keeping other parameters constant. The criteria for comparing the effect of parameters were dimensional accuracy , surface finish, tensile strength properties and hardness. Alumw.nium - 7% silicon alloy has been used for making all the castings. ,,Erthyl silicate binder has been found to be the best binder for giving best dimensional accuracy, surface finish, tensile strength and hardness.