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1997
Conference Paper
Titel
Integrating microsystems in order to produce intelligent tools
Abstract
Production technology is characterized by increasingly fierce international competition which is forcing companie to strive for higher levels of product quality and productivity, whilst at the same time, reducing prices. Accordingly, the principle objective guiding the further development of cutting processes must be to enhance efficiency and reliability. Within the past few years, the use of advanced materials and coatings has lead to a remarkable improvement in cutting tool properties. The potential of such tools can be exploited to the full, only if the cutting process is performed under absolutely stable conditions. The problem lies in the stochastic nature of process obstructions, which makes it impossible to eliminate them completely. Continuous process monitoring is, therefore, essential. Conventional process control systems deploy various types of indirect detection strategies by measure auxiliary characteristics using external sensor elements. Until now, it has not been possib le to achieve direct online detection of critical characteristics such as tool wear or temperature at the cutting edge. This problem is now being addressed within the framework of a special project which is funded by the German Research Ministery. The project partners are the Fraunhofer Institute of Production Technology in co-operation with two affiliated Fraunhofer institutes and the RWTH Aachen. The common aim is to combine the potential of thin layer technology with that of microsystems technology to develop an innovative tool. This will be achieved by integrating a specially structured sensitive layer into the wear-protecting coating of an indexable insert. This particular tool design permits the precise measurement of the temperature and wear at the cutting edge itself. The values detected are themselves used as input data to assist in the selection of optimum process parameters in order to avoid subjecting the insert to excessive stress levels and to eliminate any kind of therm a l damage to the machined surface.