The study on the tribological properties of fiber-reinforced PBT composites for various injection molding process parameters

This study investigates the influence of various, injection molding process parameters on the tribological properties of the 15 wt.% to fiber-reinforced polybutylene terephthalate (PBT). The tribological properties of the friction coefficient and volume loss are measured by using a Schwingung Reibung Verschleiss (SRV) “ball-on-plane” wear tester. The parameters of injection molding process are filling time, melt temperature, mold temperature and packing pressure. The observation of the solidified-intermediate-core morphology is mainly by the scanning electron microscopy (SEM) to define the layer thickness and to explain the influence of the fiber orientation on the tribological properties. It is found that the variation of friction coefficient and wear volume loss for the sliding direction parallel to the melt flow in different injection molding conditions have the same trend with the solidified layer change and the variation of Vickers hardness at the specimen surface. The tribological properties in the specimens of the sliding direction perpendicular and parallel to the melt flow are different. Also, the worn surfaces are observed by SEM. Grooves, cracks, cut fibers, and debonded fibers are the major wear mechanisms.