Potential of mechanical surface treatment for mould and die production

The use of mechanical surface treatment methods can extraordinarily increase the productivity in mould and die making processes. The present paper shows how deep rolling and machine hammer peening can smoothen machined surfaces in order to substitute manual polishing processes. Initial roughness of R-a > 3 mu m can be smoothed to R-a < 1 mu m, independent from the treated material. For a further improvement of the surface quality, a closer look is given to the influence of geometric effects in hammer peening. Both procedures also increase the surface hardness by work hardening. The influence on the attainable work hardening depth is examined in detail. When combined with thermal hardening operations, hardness and smoothness are still influenced positively, although this combination may be constrained by crack nucleation beneath.