In times of highly automated processes and work steps in industrial production, ever higher demands are put onto the accuracy and reliability of individual process steps. However, there are still a few exceptions where a high degree of automation does not offer a significant improvement over the current situation from the industry perspective. One of these areas is the toolmaking for the manufacturing of forming tools in the automotive and supplier industries, which are regarded as particularly important in Germany. Especially in the production of forming tools for skin parts, automation is opposed by high demands on the quality of the tools, since the processes and procedures to achieve the desired quality can only be achieved by extensive manual reworking of the surfaces. The process chain can be automated and optimized by robot-based machining with machine hammer peening to finish the surface. Both technological possibilities have so far been hindered by reservations on the part of users, which are based, for example, on the achievable accuracy of robot systems in milling.
The aim of the project is the realization and evaluation of an automated process chain for the production of forming tools in sheet metal forming with the aid of industrial robots by combining robot-supported machining and robot-supported machine hammer peening and an automated tryout process. For this reason, the comparison of the simulated with the real component geometries is indispensable and tools and products must be digitized (Figure 1). For the first time, this makes it possible to take a holistic view of the tool manufacturing process and thus provide data for subsequent repairs and revisions or geometry changes.
At the beginning of the project, the current requirements of the sheet metal forming industry for the tools and the influencing factors on the component quality have to be identified in numerical process simulations. For this purpose, “errors” such as geometrical deviations, waviness and roughness are deliberately introduced into the simulation tools and the resulting product geometry is analyzed. The first complete mapping of the process chain for the manufacture of forming tools from the blank to the production process is possible through the interaction of the institutes PTW and PtU. Figure 2 illustrates how the cooperation between the two institutes is structured in the presented project. In the further course of the project, the surface quality after machining and surface posttreatment will be characterized and optimized by an iterative procedure. Due to the subsequent tryout process automated by digital image processing, tools should be available that can be integrated into the production process without any incomprehensible manufacturing steps. The project concludes with the application of the findings to a real tool of the industrial partners involved.
The PtU would like to thank the EFB, the partner institute PTW and the participating companies for their support in implementing the project.