Development and Experimental Verification of a New Roller-Coining Setup to Texture Flat and Curved Surfaces

Micro lubrication pockets decrease the frictional losses and improve the wear resistance of lubricated machine elements. Depending on the application, the pocket dimension and the area density (ratio of the projected pocket area to the non-textured area) must be optimized. Otherwise, the lubrication pockets might increase friction and wear. Besides the determination of the optimized texture, the production process needs to manufacture the pockets with high reproducibility and accuracy, since each deviation of the texture might reduce the improvement of the tribological properties. The goal of this work is to develop a new forming setup capable of decreasing the influence of deviations in the material, of the tool or due to a process inaccuracy ́s. Therefore, a roller-coining process based on a pneumatic system was developed to keep the forming force and thus the pocket dimension constant. This setup was as well used to texture the roller, since the manufacturing of a prominent micro texture on a curved surface with high tolerances is a difficult task for other texturing methods. The experimental verification of the setup showed that by using the pneumatic setup the standard deviation of the pocket depth was reduced by an average factor of 1.9.