Opportunities, problems and solutions when instrumenting a machine tool for monitoring of cutting forces and vibrations

摘要

The ability to monitor the behaviour of machine tools and cutting processes is important both from a research perspective as well as in industrial applications such as adaptive control, condition monitoring, process optimization and quality control. The division of Manufacturing Engineering at Lulea University of Technology has been carrying out research in the area of high speed and multi axis (5-axis) machining since the mid 1990s. This European and nationally funded research, much of it carried out with Nottingham University and Sandvik Coromant, as well as in manufacturing companies in Sweden and the UK, has focused on understanding the possibilities offered by 5-axis/high-speed machining, as well as understanding the machining process. This initially empirical work has become more qualitative through the development of an instrumented machine tool test bed based on a 5-axis Leichti Turbomill equipped with a 24,000 rpm spindle and fast controller. The machine installation costs approximately 1.000.000 USD. The instrumentation that has been implemented includes piezo-electric force transducers in the machine table whilst ongoing work will move the research focus towards monitoring vibration in the workpiece for which accelerometers and acoustic emission sensors will be used. The work presented will highlight the problems and solutions involved in creating the present test bed as well as indicating future research directions and challenges.