Optimizing process parameters to reduce blowholes in high pressure die casting using Taguchi methodology

Abstract

Products manufactured from every manufacturing process exhibit some defects. To supply quality products to the customer these defects must be reduced. The motivation for this work is to reduce defects in end products reaching customers, thereby increasing productivity. The objective of present work is to reduce the rejection of parts due to blowhole defects that arise during High Pressure Die Casting (HPDC) process. The casting product selected for this study is rack housing made of aluminium alloy (ADC 12) connected with steering column of automobiles. The process parameters taken for study are Limit Switch Position, Intensification Pressure, Phase-1 Velocity and Phase-2 Velocity. Density of casting is chosen as the response factor for the parameters taken for study. Taguchi parameter design approach is used to optimize the process parameters. By varying the selected process parameters with various levels obtained through Taguchi method different experiments were conducted. The experiments are conducted based on L25 orthogonal array. To determine the percent contribution of various process parameters ANOVA have been performed. The optimum process parameters were obtained for minimum blowhole in HPDC of ADC 12 alloy. The optimum process parameters level obtained using Taguchi technique to minimize castings defects for Limit Switch Position, Intensification Pressure, Phase-1 Velocity and Phase-2 Velocity are 170 mm, 300 kg/cm2, 1 m/s and 4 m/s respectively.