Sintering study of 316L stainless steel metal injection molding parts using Taguchi method: final density

Sintering is a key step in the metal injection molding process, which affects the final density as well as the mechanical properties of the sintered part. To achieve a high final density, the effects of various sintering factors pertaining to the temperature–time profile and sintering atmosphere have to be characterized and optimized as well. This paper reports the use of Taguchi method in characterizing and optimizing the process factors for sintering water-atomized 316L stainless steel (of average size 6 μm). The effects of four sintering factors: sintering temperature, heating rate, sintering time and sintering atmosphere on the final density were studied. The various factors were assigned to an L9 orthogonal array. It was found that all the chosen sintering factors have significant effects on the final density. Optimum fractional final density of 96.14% of wrought material was achieved with a sintering temperature of 1250°C, a heating rate of 20°C min−1 and isothermal heating at 1250°C for 90 min in a vacuum atmosphere. Confirmatory experiments have produced results that lay within the 90% confidence interval.