A compensation strategy for geometric inaccuracies of hot incrementally formed parts

Abstract

The incremental sheet forming (ISF) offers high geometrical form flexibility without the need of any part-dependent tools. However, the industrial application of incremental sheet metal forming is still limited by certain constraints, e.g. the low geometrical accuracy and the small number of formable alloys. One method to overcome the stated constraints is to use the advantages of metal forming at elevated temperatures. Literature shows the benefits of hot forming, e.g. to decrease the resulting forming forces, to increase the number of formable materials, and to enlarge the achievable deformation, but also the negative effects of forming at elevated temperatures. One of those negative effects is that hot formed parts tend to be smaller than parts which have been formed at room temperature. The paper presents a new approach to compensate the resulting inaccuracies of hot formed parts. More precisely, an online compensation strategy is presented which continuously calculates the present part deviation for each point of the tool path according to the actual process parameters and which adds a movement in the opposite direction of the deviation.