Study on the mechanical, friction and wear properties of modified polyoxymethylene under free abrasive condition

The mechanical, friction and wear properties of different modified polyoxymethylene (POM) are presented in the paper under free abrasive grinding condition. The shore hardness and elastic modulus of the POM matrix increased with carbon fiber (CF) filling, its shore hardness and elastic modulus were 85 HD and 5000 MPa, respectively. The hardness and elastic modulus of the POM matrix decreased with polytetrafluoroethylene (PTFE) and graphite (C) filling. The average coefficient of friction of POM was 0.254. When PTFE, CF, and graphite were added, the coefficient of friction of the POM would be reduced under free abrasive condition. The coefficient of friction of POM filled with PTFE or graphite was about 0.15, the coefficient of friction of POM filled with CF was about 0.18. It could be seen from the orthogonal test analysis that the wear resistance of four types of materials was CF-POM > POM > PTFE-POM > C-POM. When the test duration was 1.5 h, the wear amount of C-POM was between 3 and 9 mg, the wear amount of CF-POM was less than 1.23 mg. The speed and load were the main factors affecting the wear amount of these materials, followed by the abrasive particle diameter, and the abrasive mass fraction had the least effect on them.