Targeted surface layer properties by in-process-monitoring and adaptive process control during grinding

• Applicants: Professor Dr.-Ing. Martin Dix; Dr.-Ing. Jérémy Epp; Professor Dr.-Ing. Bernhard Karpuschewski
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 401804277

Aim of this project is the development of a process control of grinding processes for the adjustment of surface and subsurface properties based on in-process measured signals.In the first project phase an in-process monitoring of the surface and subsurface condition was realized as a basis for the envisaged control. After developing procedures for the implementation and wear protection of the sensor, changes of the residual stress state were detected by in-process measurements of the Barkhausen noise before the occurrence of visible grinding burn. Additionally process knowledge was used by an analytically derived thermal process limit. By monitoring the specific grinding power Pc“ (related to contact zone) and the contact time ∆t, grinding burn revealed by nital etching or metallographic examination can be avoided for different grinding processes (generating grinding, external cylindrical grinding, surface grinding, profile grinding).In phase 2, particularly the signals of the piezoelectric force measurement (grinding power Pc) and the in-process micromagnetic analysis will be combined with the process knowledge to a soft sensor signal. The work required for this includes the validation of the process model respectively the process limit for different contact times, grinding processes and grinding wheels. Furthermore investigations on the robustness of the sensor components as well as on the generation of micromagnetic signals and signal changes are targeted. The setup of a process-integrated and an in-process control for cylindrical and non-cylindrical grinding is aimed to compensate disturbing factors like inconsistent surface and subsurface material conditions before grinding, non-uniform distribution of the grinding stock and irregularities of the grinding process (e.g. wear of the grinding wheel). The final aim is to ensure reproducible optimal surface and subsurface material properties after the grinding process.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2086: Surface Conditioning in Machining Processes