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Priority Program 2086: Surface Conditioning in Machining (SPP2086)

Targeted adjustment of edge zone properties by means of in-process monitoring and adaptive process control during grinding

All manufacturing processes influence the boundary layer state of a component, which can be described e.g. by residual stress state, strain hardening state and topography. This boundary layer condition determines the component properties under vibrational or tribological stress, among other things. The targeted utilization of a robustly adjusted boundary layer condition in manufacturing processes thus leads to improved component lifetimes and reliability. The greatest challenge in this area is currently the robust and efficient detection of the boundary layer condition in the process and the dynamic pre-control and control of machining processes with regard to the boundary layer conditions.
The aim of the work in the priority program is to develop process controls for machining processes using a combination of sensors and process knowledge in the form of process, geometry and material models in order to simultaneously set defined geometries and boundary layer states in metallic components. This is intended to ensure these boundary layer states and thus also the properties of the manufactured components even in the presence of observable or hidden disturbance variables in the process.
Due to its quality-determining significance, hard finishing by grinding requires a high degree of analytical understanding and empirical knowledge in the event of any susceptibility to interference. The non-constant results of grinding processes can be attributed to different phenomena, which can be caused by both the tool and the workpiece. While the adjustment of the desired dimensional and form accuracy is nowadays facilitated by various auxiliary tools, hardly any aids exist for controlling the thermomechanical process effect and thus for the targeted adjustment of the edge zone properties.
Within the scope of the project "Targeted adjustment of edge zone properties by means of in-process monitoring and adaptive process control during grinding" (cooperation of Leibniz-IWT, University of Bremen and Fraunhofer IWU, Chemnitz), an in-process or near-process control system is aimed at, which should enable the targeted adjustment of edge zone properties by the grinding process. Two analogy experiments for industrial manufacturing processes are considered: Analogy tests for discontinuous profile grinding and for non-circular grinding. After in-process monitoring of the edge zone condition during grinding was implemented in the first funding phase, a control system based on the requirements of industrial manufacturing is to be set up in the second funding phase. The combination of magnetic Barkhausen noise and a process model based on the grinding power to a soft sensor signal enables the clear differentiation of different thermo-mechanically influenced edge zone states.
Further information on the priority program.