Quality Improvement in a Low Pressure Die Casting Process of Alloy Wheels by Applying Box-Behnken Design

Abstract

This research focuses on the reduction of defective alloy wheels in low pressure die casting (LPDC) process. Currently, the shrinkage porosity is a major defect found in LPDC process. The defective rate of shrinkage porosity is 31.4% on average. The Box-Behnken design is conducted to investigate the effect of factors to the shrinkage porosity defect. There are four potential factors including die coating thickness, mold temperature, cycle time, and aluminum temperature. The estimated coefficient and the optimization approach are utilized to yield us the suitable process parameters which are the die coating thickness of 60 um, mold temperature of 480 ℃, the cycle time of 9 min and the aluminum temperature of 689 ℃. After implementation of new process parameters, it is found that the defective rate of shrinkage porosity is reduced to 9.8% which achieves the target. The cost of rework can be decreased and the reliability of alloy wheels is improved.