Mechanical Properties and Microfabrication Study of Injection Molding on Ultra-High Molecular Weight Polyethylene Polymer

In this study, the experiments were divided into three categories: tensile strength experiments, wear test experiments and microstructure molding experiments. Firstly, as the tensile strength of UHMWPE being concerned, the experimental results indicate that the effect of process parameters is relatively smaller than weld line on the tensile strength of specimens. The frictional heating could enhance the molecular bonding and self-diffusion in the frozen layer of both sides on the weld line region during the experimental observations. Secondly, as the wear behavior being concerned, the experimental results show that the friction coefficient increase linearly with the increase of sliding frequency. The results also indicate that the wear resistance in the sliding direction perpendicular to the melt flow direction is stronger than that in the sliding direction parallel with the melt flow direction. The main wear mechanisms in dry sliding conditions were plastic deformations and wrinkled formations observed by optical microscopy. Thirdly, as the micro-fabrication being concerned, replication accuracy was examined for injection molding and injection compression molding. Both the injection molding parts and the injection compression molding parts were observed under microscope to compare their replication accuracy. The experimental results show that the micro-structures can be filled with UHMWPE by injection molding and injection compression molding technology. The height and shape of microstructure were affected by process parameters. Thus for better replication accuracy, both injection molding and injection compression molding processes will be in need of a parametric optimization.