Friction and wear behavior of polylactic acid (PLA) with different fill patterns and densities

Abstract

In recent years, parts built by fused deposition modeling (FDM) techniques with polylactic acid (PLA) have been widely used for various applications. In transportation technologies, these materials and techniques are used to produce structural and mechanical components of scale vehicle prototypes. The tribological properties of parts manufactured by these techniques not only depend on the material but also on the type of density and filling pattern. The objective of this work is to compare the wear and friction characteristics of PLA pins with two patterns and three different filler densities on abrasive discs in Pin-on-Disk tests. The tests were carried out at a speed of 0.033 m/s with a load of 40 N for 1800 s. It has been observed that the deposition density has a greater influence on tribological parameters than the filling pattern. A clear trend of reduced wear rate is observed with increasing filling density. Pins with 100% filling density show a reduction in wear rate of 44% compared to pins with 50% filling density in tests with abrasive paper (grit 150). In tests with finer abrasive papers (grit 600), a reduction in wear is also observed with increasing filler density. The friction behavior remains practically stable regardless of pattern and filling density for the same abrasive paper on the counterpart, showing an average friction coefficient in the stable period of 0.6.