This work presents a mechanical analysis of tangential contact using molecular dynamics simulations. Scratch tests with a conical tip on amorphous polymer surfaces were simulated at various temperatures, scratching velocities, roughnesses of the tip and with various interactions between the tip and the monomers. The local friction coefficient for the different contact conditions (temperature, tip roughness and scratching velocity) was calculated by studying the apparent friction and the contact asymmetry. The results are in good agreement with experimental data from tests on classical polymer surfaces on a microscopic scale.