The effects of gate size in powder injection molding

This paper studies the effects of gate size on the quality of powder injected molded (green) parts and the cavity filling pattern. A total of five rectangular gates with different shape factors (ratio between the width and the depth of the gate) were used. A weight and density analysis was performed on the samples molded for each of the five gates. It was found that the gate with a shape factor of 3.8 gives the highest weight and density. The result also indicates that an increase in the width or the depth of the gate will give different results even though the total cross sectional area of the gate is kept constant. Samples molded with gates of larger depth tend to have higher weight and density. The cavity filling pattern and microstructure were observed for each gate size.