The processes of roller burnishing, deep rolling and machine hammer are is used for smoothing the surface roughness, increasing the life time of metal components and also for micro structuring of surfaces with defined geometries. These technologies are unique in that they are the only processes for increasing component service life that combine the effects of the generation of residual compressive stresses, the cold working in the edge layer and the smoothing of component’s surface. These processes can be also easily integrated into an existing process chain and can be used on both conventional and CNC-controlled machine tools. This allows a workpiece to be treated in one setting directly after machining, eliminating set-up and transportation costs.
Concerning the reducing of friction and consequently increasing the wear life of sliding surfaces there are mainly two approaches. On the one hand the modification of the surface topography offers a good possibility to decrease the friction. In this context smoothing the surface enables to reduce the number of roughness peaks. As a result the load on those peaks will be transmitted on a bigger contact surface and thus the surface pressure will increase. On the other hand reducing the surface roughness leads to the rupture of the lubricating film, which can’t be held anymore between the roughness peaks. Therefore in addition to optimized smoothed surfaces, a sufficient supply of lubricant is also necessary in order to decrease the friction and thus the wear of sliding surfaces. At this conjunction, structuring the surfaces with micro hydrostatic lubrication pockets enables holding the lubricant in the contact zone and accordingly optimizing the friction conditions of sliding surfaces.
In light of the above, roller burnishing, deep rolling and machine hammer peening provide reliable, efficient and economical possibilities for manufacturing low friction surfaces and additionally increasing the component service. In this contribution these processes will be expounded as well as the approaches using the correspondent technologies to reduce the friction on sliding surfaces and simultaneously increase the fatigue strength of the metal components.