New methods of surface engineering in forming tools development

Due to high thermal and mechanical loads for high security-related aluminium parts new coatings must be developed for forming tools. In the paper some FEA models are presented to simulate the behaviour of coated surfaces of forming tools. The intention is to analyze fine geometric structures in high loaded tools. In a first approach elastic-plastic behaviour has been assumed. It is known that the accuracy of FEA improves with a finer discretization or a higher order of the elements. It could be shown that the quality of the FEM mesh influences the results in a significant way. For numerical reasons the mesh has to be as homogeneous as possible in areas with microscopic structures even so when the grain or the molecular structure are not an object of interest. That means a very high number of small sized finite elements respectively a high order of elements. Thereby computational resources are highly stressed. At present a number of one million degrees of freedom seems to be the maximum for such finite element models. An analysis of the failure behaviour of coated tools close to reality requires non-linear contact models. As a first approach the cracking of coatings under pure bending stress for different substrate-coating configurations has been analyzed. In order to test the substrate-coating model an indenter test has been simulated