Performance Evaluation of machine tools : A methodology for loaded testing of machine tools

Sammanfattning: Machine tools comprise the basic elements of manufacturing. Evaluationof their performance and reliability are necessary for ensuring productquality. A key for improving their performance is to understand how physicalattributes of the system, like stiffness and geometric accuracy, are affectingthe operational accuracy and how it is changing during operation. Hence inorder to understand and quantify this behavior of the physical quantitiesmeasurement and modelling is imperative.A methodology is presented for the measurement and identificationof machine tool’s quasi-static stiffness under loaded kinematic conditions.Aiming at capturing and understanding machine tool quasi-static stiffnessas close as possible to the real operation, the methodology is focusingon evaluation under operational like conditions. A holistic perspective isadopted, measuring quasi-static stiffness inside the machine work envelope,at the Tool Center Point (TCP). Various parts of the methodological stepsare presented and exemplified by measurement examples from the publishedpapers.Two measurement instruments are presented in conjunction to themethodology, that enable the measurement of quasi-static stiffness of linearand rotary axes, offering the possibility to measure three and five axismachine tools. The goal of the this thesis is thus two fold, first to expand thedomain knowledge and understanding in machine tool testing and potentiallymake a step towards the further development of machine tool loaded testingfor performance evaluation.