Smart sensor systems for machine tools

Adaptive machine tools with multi-sensor tool holders

The efficiency of machine tools is based largely on highly developed electro-mechanical sub-assemblies. However, smart, embedded systems have so far failed to advance very far. The use of sensors is usually limited to the most important safety functions or to automatic calibration of tool and workpiece. There is usually a centralized information processing unit which collects all of the signals in one operation and analyzes them.  

However, adaptive production can be achieved only when
autonomous, sensor-assisted systems are integrated in machine tools. Only then machines and equipment are able to control the production process to an optimum degree, even under changing conditions. As a result of higher sensor density, it is now possible to create a sufficiently wide base of information to allow the embedded systems to take over process control functions.

The Fraunhofer IPT is developing smart sensor systems which will be integrated within the machine in order to collect the required process and product information in-process and to make it available to the control systems. One of the main challenges in this context will relate to the need for process-oriented information processing, i.e. how to transform raw data such as electric currents into concrete statements regarding process forces or vibrations.

In the “Sens4Tool” research project a multi-sensor tool holder capable of recording size, force, moments, vibrations and tool temperature within an on-going process, is being developed in a collaborative venture with several industrial companies. In addition to the sensor, a data processing sub-assembly will be integrated within the tool holder. This permits interpretable information regarding tool wear or material faults in the part, for example, to be acquired during the machining process.