Multi-scale analysis of the material separation mechanisms in grinding of unreinforced thermoplastics

• Applicant: Professor Dr.-Ing. Dirk Biermann
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 326745661

Due to the positive properties of plastics such as low density, high forming flexibility and their energy-efficient production, classic constructive materials such as metal and ceramics are increasingly replaced and complemented. Grinding is a manufacturing process with geometrically undefined cutting edges, which is often used as the finishing process to produce high workpiece qualities and high dimensional shape and surface accuracies. In the state of the art, only a few scientific studies deal with the grinding process of unreinforced thermoplastics. For this reason, fundamental investigations on the grinding processes of the unreinforced thermoplastic polymers Polyoxymethylen Copolymer (POM-C) and Polyetheretherketon (PEEK) were carried out in the first project. Based on these results, process parameters have been found which lead to a reliable grinding process with regard to the occurring process forces and the produced surface quality. Additionally, single grain scratch tests were carried out to analyze the local material separation mechanisms and the chip formation. The results of the single grain scratch tests were summarized to a simplified process model of the grain engagement for each thermoplastic. In the previous grinding investigations, grinding wheel wear was circumvented by regular dressing processes and thus was neglected. However, the grinding wheel wear has a significant influence on the effectiveness of the grinding processes of thermoplastics. That is why fundamental investigations with regard to the wheel wear will be carried out in this project. The results of the grinding wheel wear tests will be connected with the results from the initial project. Additionally, the process parameters which were found for a safe grinding process with regard to high surface quality and the occurring process forces will be extended by the grinding wheel wear. Based on these results, it is possible to design an effective grinding process with minimized wheel wear for the machining of non-reinforced thermoplastics.

• DFG Programme: Research Grants