Minimizing the casting defects in high-pressure die casting using Taguchi analysis

High-Pressure Die Casting (HPDC) is one of the major production processes of automotive industry, widely used to manufacture geometrically complex nonferrous castings. The mechanical strength and microstructure of HPDC-manufactured products changes with variation in several process control parameters such as injection pressure, molten temperature, 1st and 2nd stage plunger velocity, cooling temperature, etc. Since these process parameters directly affect casting quality, their optimum combination is needed to maximize the productivity of process and minimize casting defects such as porosity, pinholes, blowholes, inclusions, etc. Hence, to tackle this problem, an approach is presented in this paper that minimizes the major casting defect, i.e., porosity, in the HPDC process by optimizing controlling parameters through Design of Experiments (DOE) in combination with a Taguchi Analysis. The results obtained showed that cooling time, injection pressure, and 2nd stage plunger velocity have a major influence on the response factor (density of the cast part). It was also concluded that, by using a 178 bar injection pressure, 665 °C molten temperature, 5 second cooling time, 210 °C mold temperature, 0.20 m·s−1 1st stage plunger velocity, and 6.0 m·s−1 2nd stage plunger velocity, the rejection rate of the selected part due to porosity was reduced by 61%.