Component Synthesis of Machine Tool and Cutter for Process Optimisation

Licentiate thesis, 2012

Metal cutting is today one of the leading forming processes in the manufacturing industry. The metal cutting industry houses several actors providing machine tools and cutting tools with a fierce competition as a consequence. Extensive efforts are made to improve the performance of both machine tools and cutting tools. Performance improvements are not solely restricted to produce stronger and more durable machine tools and cutting tools. It also includes knowledge about how the machine tools and cutting tools should be used to perform at an optimum of their assembled capacity. This work presents a methodology to synthesise the dynamic behaviour of a machine tool and cutting tool assembly based on component models of the machine tool and the cutting tool. To treat the structure as an assembly of subcomponents aims first of all to reduce measurement effort to get the receptance at the tip of the machine tool/cutting tool which is needed for process stability optimisation. This methodology compares to today's state of the art methodology which require experimental modal analysis (EMA) for each cutting tool of interests mounted in the machine tool. The subcomponent approach presented here limits the EMA to the machine tool component. The machine tool component model is then connected to a component FE-model of the cutting tool of interest. The subcomponents models are obtained and coupled based on state-space formulation, a technique that is new to component synthesis of machine tool/cutting tool structures. A sensitivity analysis is also presented to raise awareness of crucial parameters that influences the result of the synthesised system. The understanding about how to assign cutting process parameters in order to optimise a cutting operation with respect to machining stability is of utmost importance to provide good productivity and process stability. This methodology opens windows not only to optimisation of an existing cutting tool but it also permits tailored cutting tool solutions for existing machining operations.