Fraunhofer Institute for Electronic Nano Systems
In metal-cutting machines, workpiece clamping is an essential connecting element between the workpiece and the machine element, because faulty workpiece clamping always has an immediate and direct effect on machining quality and process reliability. The methods currently used to measure clamping forces have serious disadvantages: they are expensive, large and therefore hardly suitable for online measurement. The objectives of the project were to evaluate an existing foil-based sensor principle for measuring an axial force with regard to the proof of robustness against continuous, cyclic loads and to expand the current structure constructively for application-oriented use cases. For this purpose, capacitive sensors with solder connection and flexible connection option were created, evaluation electronics and software components for a wireless transmission unit were implemented and load tests (11,000 cycles) were carried out on demonstrators with force applications between 0.01 - 20 kN.