An effective model test for tool life estimation

Motivation

The competitiveness of sheet metal processing small and medium-sized enterprises (SMEs) depends highly on efficient and effective processing of sheet metal components. For this reason, a better understanding and control of tool wear is a key factor for efficient sheet metal processing. Model tests such as strip drawing tests offer the possibility to evaluate the wear resistance of forming tools in certain tribological systems. However, the model test cannot represent the wear development or tool life in the real forming process effectively. Therefore, an investigation of the consistency of the wear development between model test and real process is desirable.

Objective

The aim of the project is to develop a method for predicting tool life and wear development in real forming processes through a model test in laboratory environment. In addition, the tool lives under increased load levels are also determined in the model test. For this purpose it will be examined whether the real tool life can be approximated by tests at higher tribological load levels.

Solution

At the beginning of the project, the tribological loads in the real forming process, such as normal contact stress and temperature field in the forming tool, are determined through FEM simulation. By selecting suitable wear models, the wear development is determined. Based on the results of tribological loads and estimated wear development, a specific tool is to be designed for model tests, which can be used to illustrate the wear development of the real process in model tests. After the manufacturing of the designed tools, the lifetime of the tool is determined in the model test under process-similar and elevated load levels. The determined tool life and its scatter form the wear resistance diagram, which represents the expected values of the tool life and its uncertainties.

Figure – Wear resistance characteristic diagram

Finally, an estimation procedure is developed so that the wear resistance characteristic curve can be derived under the entire load level.

Acknowledgements

The PtU thanks the AiF, the European Research Association for Sheet Metal Working e.V. (EFB) as well as the participating companies for their support in the implementation of the IGF project number 21116 N.