The comprehensive analysis of what occurs with the two polymers (Table 1) shows that the temperature is not the dominant factor in the behaviour of the friction force, although its effect is more pronounced in the case of PC. The effect of the contact pressure is similar for both materials, being more important in the friction force behaviour than the temperature in the case of PP. The roughness is more influent in the case of PP this impact being more significant at higher temperatures. Thus, it appears that the most important factor affecting the friction force in all materials tested is the roughness.