Functionalization of Additively Manufactured Hot Stamping Tools Using Ball Burnishing

Funding: German Research Foundation (DFG)
Project: 417202720
Contact: Anna Komodromos M. Sc.

Hot stamping is used in sheet metal forming in order to use the increased forming capacity due to high temperatures and the increase in strength due to quenching.

For this purpose, cooling channels, which are usually produced using machining processes, are integrated into the tools. Within the scope of the project the development of additively manufactured hot stamping tools by means of direct energy deposition is intended to enable the channels to be positioned as close as possible to the surface. This avoids local overheating of the tool. Since direct energy deposition creates a very rough, wavy surface, post-processing is necessary. This is done by means of incremental ball burnishing (see figure). Here, the tool surfaces can be adjusted locally. In this way, a targeted influence on the heat transfer and the material flow during hot stamping is to be achieved. Initial studies of ball burnishing additively manufactured surfaces show that the high roughness can be reduced by up to 75%, depending on the hardness of the tool steel powder.

Process steps for additively manufactured and ball-burnished hot stamping tools