Effect of surface roughness on friction induced noise in cast polyamide

In this study, an experimental analysis has been made on the effect of surface roughness on noise characteristics of polymers in dry sliding conditions. A pin on ring test apparatus has been utilized to analyze the noise characteristics of polymers used in industrial applications. Normal load, sliding speed and surface roughness are adjustable parameters, friction force, number of revolution and sound pressure level are the parameters recorded during the experiments. Cast polyamide 6 (PA) and oil impregnated cast polyamide 6 are used in experiments. Sound pressure level measurements are carried out for 20 N, 40 N and 80 N normal loads and eight different speeds in the range of 0,2-1,6 m/s. It is concluded that sound pressure level generally does not vary with the normal load whereas it slightly increases with the sliding speed in the center frequencies of 1/3 octave bands. The coefficient of friction increases with increasing sliding speed. In the cases where the coefficient of friction is relatively high, friction induced vibration has a significant effect on the increase of sound pressure level. Generally, for unfilled cast PA 6 in low surface roughness, it can be concluded that, high frequency sound pressure level increases with sliding distance.