Tribological Behaviour of 3D printed Polylactic Acid (PLA) Sliding Against Steel at Different Sliding Speed

In this study, the tribological properties of fused deposition modelling (FDM) 3D printed Polylactic Acid (PLA) is studied when it slides against a steel disk at various speeds. 3D printed pins were printed using PRUSA MINI+ 3D Printer according to recommended printing parameters. Pin on disc tribological tests were conducted at normal load of 20 N, sliding time of 20 minutes, and linear sliding speeds of 0.46, 0.58, 0.7 and 0.81 m/s. Experiment results showed that wear rate increases with the increase of sliding speed, and coefficient of friction decreases with the increase in sliding speed. Observation of worn surfaces suggested the major wear mechanisms are abrasion, adhesion, and delamination. The difference in tribological behaviour was mainly caused by hardness-temperature relationship. The main anomaly that occurred in the observed trends are that the pin melted at highest sliding speed, resulting in opposite trends. The increase in temperature at the contact point of the pin and sliding disk weakens PLA pins. Therefore, 3D printed PLA can be used in a temperature-controlled low speed sliding application such as a lubricated gear and not for applications that subjected to high sliding speeds and temperature.