Warm compaction and free sintering of ultra high molecular weight polyethylene

Warm compaction recently developed for P/M technologies has been successfully used for the compaction of ultra high molecular weight polyethylene (UHMWPE) powders. Processing parameters such as temperature and pressure of compaction, compaction rate and free sintering temperature have been examined. Compared to cold compaction, warm compaction of UHMWPE powders at temperatures in the 65 to 125 degrees C range enabled significant improvement in particle deformation, leading to better densification and higher green strength. After free sintering, parts with little porosity (4-8% compared to more than 20% porosity by the cold compaction process), and with mechanical properties similar to parts made by compression molding were obtained. This work shows there is good potential in the use of warm compaction for the production of net shape formed parts from polymeric powders.