Methodology for additive repair of press hardening dies using generic die segments and targeted deposition strategy

Press hardening is extensively used in the automotive, agricultural and other branches of industry to efficiently produce high-strength parts by integrating a heat treatment into the hot forming process. One of the major challenges in press hardening is the die wear due to high cyclic thermomechanical loading. The wear leads to die geometry changes and thus to unacceptable tolerances of components and deviations from intended mechanical properties due to the lower cooling rates in these areas. The most promising approach for extending the die lifetime is the application of additive technologies for their repair. Some examples of die repair using L-DED and WA-DED additive technologies are presented in the literature, but no guidelines were provided. This paper proposes a methodology for the additive repair of an arbitrarily shaped die surface using generic segments. The main approach is to decompose the die geometry into elementary geometric segment shapes and to develop an optimal repair strategy for each segment shape. The targeted deposition strategy proposed in the paper also helps to control the metal flow during hot stamping and increases the fatigue life of the repaired tool. The proposed approach has been validated on a specific die insert utilizing the L-DED process.