Design and fabrication of two component powder injection moulding

This research explores and validates the feasibility of a simultaneous two-component powder injection moulding (2C-PEVI) process using ceramic (alumina) and metallic (stainless steel) feedstocks. The study addresses key challenges in producing defect-free, multi-material components by analysing thermal and rheological properties, simulating interfacial behaviour, and evaluating the mouldability of the two materials using a custom-built 2C-PEVI machine designed for simultaneous co-injection. Differential Scanning Calorimetry (DSC) showed both binder systems began melting at approximately 55 °C, while Thermogravimetric Analysis (TGA) revealed total weight losses of 17.4% for alumina and 6.43% for stainless steel, confirming typical thermal behaviour during binder removal. Rheological tests confirmed pseudoplastic flow with shear sensitivity index below 1. Activation energy ranged from 0.1-2.9 kJ/mol for alumina and 7.13-10.43 kJ/mol for stainless steel, indicating suitability for injection moulding of complex geometries. Moldex3D simulations assessed interfacial behaviour during co-injection. Symmetrical weld lines were achieved with injection times between 0.4 s and 0.5 s, and improved results occurred when the injection pressure of polypropylene was lower than that of LDPE. Balanced injection profiles minimized weld line defects and enhanced interface quality. Experimental trials using the newly developed 2C-PEVI machine confirmed the feasibility of simultaneous co-injection. Optimal injection temperatures were identified as 190 °C for stainless steel and 230 °C for alumina, based on flow performance and alignment with simulation outcomes. In conclusion, this study demonstrates that simultaneous 2C-PEVI is a viable and effective method for fabricating multi-material components. It offers reduced cycle time, improved interfacial control, and contributes valuable data toward advancing process design for multi-material injection moulding.