Reduction of scrap percentage of cast parts by optimizing the process parameters

Abstract

Casting is a widely used manufacturing process in the automotive industry. Die casting is the most popular type of casting processes. But the fact observed in many industries is the rising number of scraps or wastages occurring after the process. Thus, this paper is primarily intended on understanding the die-casting process and the factors governing them. In this paper, the part to be studied is a throttle body and the raw material used for its production is AlSi9Cu3. The main concern in this part is the occurrence of defects such as bad filling, heat bubbles, and porosity. Thus, it is important to perform process optimization. To perform the optimization, techniques such as Design of Experiments (DOE), ANOVA analysis, numerical simulations, brainstorming and quality tools are used. A Taguchi orthogonal array is designed with 18 set of experiments in Minitab 18 and 3 sets of experiments are used for simulation in the Quikcast software. Signal-to-noise (S/N) ratios are calculated with Minitab 18, in which rejection percentage is considered as the response variable with the concept of “Smaller the better” characteristics. With the help of the Quikcast software, the filling time and total shrinkage porosity distribution were determined. Thus, these techniques, after their implementation, enabled to reduce the overall scrap percentage from 14% to 9%.