Residual stresses in grinding of forming tools with toric grinding pins

Abstract

The subsurface residual stress state of forming tools is an important factor for the lifetime of these tools. This is especially important for tools used in processes like sheet-bulk metal forming, where very high process loads occur in the tools during the forming operation. Grinding as one of the last process steps for manufacturing of these tools significantly affects the subsurface residual stress state. For five-axis grinding, toric tools are advantageous, because constant contact conditions are realized even on complex free form surfaces. Previous work identified the major process and tool parameters for influencing the residual stress state due to grinding with toric grinding pins. This paper investigates the quantitative correlations between the main parametersfeed rate and cutting grain size and the resulting residual stresses in a full factorial experimental design for the lateral grinding strategy. An empirical model is determined from the results of the experiments, which allows to predict these residual stresses for toric pin grinding. Additional grinding force measurements and cutting simulations are conducted to gain additional insight in the generation of residual stresses through grinding with toric pins.