Monitoring system for high speed wood machining processes

The improvement of product quality as well as the increase of production efficiency is inevitable in modern manufacturing processes. In this regard an increased cutting speed causes dangerous process situations in respect to operator safety and machine damage. In addition to that wood working machines generally do not use process monitoring systems, e. g. tool breakage monitoring. The aim of this project was the development of a process monitoring system to increase safety in wood working processes. Therefore, the Institute of Machine Tools and Production Technology (IWF) and the Fraunhofer-Institute of Surface Engineering and Thin Films (FhG IST) developed a sensor-integrated tool holder, which is able to detect clamping forces and unbalances during the process. The hollow shank taper 'HSK-63-F' was chosen as tool holder as it is used in the majority of applications in wood working processes. The clamping and balance conditions are measured by an embedded piezo-resistive thin film sensor at the planar contact surface. To ensure a contact-free signal transmission a telemetric system was used. The interaction between this monitoring system and the machine control automatically activates an emergency stop. Hence, a system was developed which significantly increases the process safety during the run-up and the idle speed phase of the spindle.