INVESTIGATION OF VARIOUS PARAMETERS OF HOT COATING OF RESIN BONDED SAND FOR SHELL MOULDING PROCESS

Abstract

Investigations were carried out to study the various parameters of hot coating of resin bounded sand in shell moulding process. Hot coated shell sand was prepared by coating resin on sand heated in the range of 106 - ~ . Hexamine was added as an accelerator at a temperature in the range of 90 - I W°C. Calcium stearate was added just before sand start making lumps. Sand was mixed in a special type shell sand mixer. Test specimens were made from the prepared shell sand for tensile and bending test. Test specimens made of standard size were tested on sand strength testing machine. Using experimental design technique, the effect of various parameters were studied. Also the surface roughness of the casting made by the shell moulding process using the prepared sands were measured. Regression Equation, for tensile and bending were formulated. Various plots between strengths and independent variables were made and analysed. Suitable values of various parameters like resin percentage, hexamine percentage calcium stearate percentage, temperature of sand when resin is added and when hexa is added were determined from the analysis.