Optimization of Sand Casting Parameters for Reducing Casting Defects Using Taguchi Method and Casting Simulation Technique

Abstract

The aim of the present work is to reduce the rejection rate of cast products in a foundry shop due to casting defects in sand casting process using a statistical tool namely Taguchi method and a computer aided simulation technique. Conventional techniques require a larger number of trials for checking outputs when the variety of input conditions increase and this problem can be reduced using this two techniques. In this investigation, the various casting process parameters such as moisture content (%), green compression strength (g/cm2) and permeability number are considered and organized according to Taguchi L18 orthogonal array. Taguchi approach is utilized to find out the most significant control factors which will reduce casting defects. Besides, the percentage contribution of process parameter has been determined using statistical Analysis of variance (ANOVA). Finally, the general regression equation is formulated and better cast product is obtained with less defects and it is validated by means of confirmation test. It is observed from experimental trials in foundry shop that average value of minimum casting defect is 3.1% for aluminum flywheel. Not only that in this thesis an attempt has been taken to redesign gating and feeding system for producing a casting free from defects. Defects such as shrinkage porosity, improper solidification, air entrapment, mold erosion are directly related with gating and feeding system design. Number of iterations using casting simulation software are performed for mold filling and solidification analysis to reduce the rejection level in cast component. With new gating and feeding system design improvement in casting yield (about 15%) is observed.