Generation of Predetermined Surface Structures by Simulation Based Process and Tool Design When Milling Free-Formed Surfaces

Abstract

In sheet-bulk metal forming (SBMF), the high geometric complexity of workpieces and differently dimensioned functional elements within the forming tool can lead to an insufficient form filling of cavities. One approach to optimize the SBMF process are functional surface structures, which can be used to influence the contact situation between forming tool and workpiece. Therefore, the aim of this project was to create defined surface structures with specific roughness properties on forming tools for SBMF. This was realized by a milling process with intentionally induced regenerative tool vibrations and high-feed (HF) milling. For this purpose, the basics for a simulation environment were first created, within which the process parameter settings for the generation of the occurring vibration patterns were defined. The effects of the surface structures thus generated were investigated and validated both theoretically and experimentally. The results were transferred to free-form surfaces with application for the SBMF tools. Subsequently, the proceedings were extended for HF milling which proved to be advantageous to micro milling in terms of tool life, process efficiency and control. The application of quasi-deterministic patterns with different tribological properties of the surface depending on the desired local surface characteristics and the process parameter values was enabled.