Research on influencing factors and its optimization of metal powder injection molding without mold via an innovative 3D printing method

Abstract

Using laboratory-made three-dimensional (3D) printing equipment, an innovative 3D printing process without a mold, which was based on metal powder injection molding (MIM), was developed for the fabrication of complex 3D metal and alloy components. Copper powder and paraffin wax were selected for the composition of the copper paste composite. The study was performed to analyse the effects of printing process parameters on the layer-by-layer injection and forming mechanism of the copper paste. Furthermore, the effects of heating parameters during the sintering process on the microstructure and some physical properties of the samples were investigated. The results revealed that the sintering temperature of the copper paste was initiated at a lower temperature (ca. 300 °C) than that of bulk copper metal. The optimal conditions of the heating process of copper paste were explored. The optimal conditions of the sintering temperature were above 950 °C with a holding time of 120 min. Herein, a metal component was manufactured with a complex 3D structure, dense microstructure, superior metallurgical bonding and a flat surface based on our research. The results of our study demonstrate the potential to manufacture metal and alloy components by means of a low cost 3D printing technique.