CRC 747 Micro cold forming - processes, characterisation, optimisation

Schema SFB 747

Researcher: Iwona Piotrowska-Kurczewski, Phil Gralla, Jost Vehmeyer, Peter Maaß
Project funding: Deutsche Forschungsgemeinschaft (DFG)
Project sponsor: Deutsche Forschungsgemeinschaft (DFG)
Partner: BEGO Medical GmbH, Bremen
Duration: 01.01.2015 - 30.06.2017

At ZeTeM, mathematical models for machining processes have been developed, analysed and used to optimise the processes in various DFG-funded projects, so that extensive knowledge has been gathered in recent years. The focus of the work is on the one hand on the macroscopic shape and on the other hand on the microscopic surface functionalisation.

For the first time, the work now has to prove itself in an industrial project within a real process chain. Within the framework of CRC 747, an independent transfer project was realised, for which the company BEGO Medical GmbH could be won as an industrial partner. As a manufacturing service provider for dental products, such as dental prostheses and implant components, high requirements must be met in terms of dimensional deviation and economic efficiency in order to hold one's own against the competition.

As part of the transfer to industrial practice, the simulations developed in CRC 747 and the mathematical methods for inverse optimisation were transferred to the dental materials and milling tools with large length-to-diameter ratios. With conventional control, physical process influences remain unconsidered, resulting in shape deviations of the manufactured products. The developed process force models are used to compensate for the compliance of the long tools. Based on a given control and the geometric conditions of the tool cutting edge being engaged, a correction is made so that the geometric error on the workpiece is minimised. The objective is to achieve 10 microns for the shape accuracy in the critical area of the tooth stump and the tooth replacement. This corresponds to a halving of the usual values and represents a unique selling point in the production of dentures.