Design model for the knowledge-based adjustment of the edge zone and surface properties of additive-manufactured components for guided centrifugal finishing
Final Report Abstract
Guided centrifugal finishing offers the potential not only to reduce surface roughness, but also to induce residual compressive stresses in the workpiece rim zone. Due to insufficient knowledge about the contact between the abrasive media and the workpiece during guided centrifugal finishing, a knowledge-based process design is not possible. This research project therefore analysed the cause-effect relationships between the process input variables and the process result variables as a function of the process state variables in guided centrifugal finishing. Firstly, measuring systems were developed that were suitable for the empirical investigation of the contact between the abrasive media and the workpiece in robot-guided centrifugal finishing. The measuring systems were then used in empirical investigations in order to record the type of contact, the contact frequency, the contact force and the relative speed. It was shown that the formation of the stagnation point impairs the transfer of kinetic energy from the abrasive media to the workpiece. The increase in the angle of inclination reduced the formation of the stagnation point and its influence on the contact between the abrasive media and the workpiece. The process input variables influenced the contact type, the contact frequency, the contact force and the relative speed in different ways. Using the finite element method, it was shown in a numerical model that impacting abrasive media transfer a defined proportion of their kinetic energy to the workpiece. Empirical investigations were then carried out with differently pre-machined workpieces. It was shown that the contact normal force and the relative speed influence the process result variables of surface integrity differently. Using the finite element method, it was shown in a numerical model of the contact between the abrasive media and the workpiece that a limit value was reached for the maximum residual compressive stresses. Finally, an explanatory model was developed on the basis of the cause-effect relationships between the process input variables and the contact parameters and the cause-effect relationships between the process state variables and the process result variables. Finally, the explanatory model was verified by means of empirical investigations of robot-guided centrifugal finishing. For this purpose, ground workpieces were used and machined with ceramic bonded abrasive media. This was followed by machining with resin bonded abrasive media to adjust the surface roughness. The result of the research project is an explanatory model for surface integrity as a function of the process state variables in robot-guided centrifugal finishing. The results were used to define a procedure for a multi-stage process design that can be used to adjust the surface integrity of the workpiece in guided centrifugal finishing.
Publications
-
Development of measuring systems for contact force and relative velocity in robot-guided centrifugal finishing. Procedia CIRP, 104, 14-19.
Ohlert, Marius; Schriever, Tim; Prinz, Sebastian; Barth, Sebastian & Bergs, Thomas
-
Surface Modification of Inconel 718 by Robot-Guided Centrifugal Finishing and Vibratory Finishing. Lecture Notes in Mechanical Engineering, 3-7. Springer Singapore.
Ohlert, Marius; Prinz, Sebastian; Barth, Sebastian & Bergs, Thomas
-
Influence of relative velocity and contact force between abrasive media and workpiece on material removal in gyro finishing. Journal of Manufacturing Processes, 79, 614-625.
Ohlert, Marius; Brüssel, Fabian; Prinz, Sebastian; Barth, Sebastian & Bergs, Thomas
-
Contact between Abrasive Media and Workpiece in Robot-guided Centrifugal Finishing. 1. Auflage., Aachen: Apprimus Verlag, zugleich Dissertation RWTH Aachen
Ohlert, M.
