Evaluation of machine-tool motion accuracy using a CNC machining centre in micro-milling processes

The demand for micro holes, micro-moulds and micro forms continues to grow as high-tech industries demand miniaturized products. Sectors such as aerospace, microelectronics, medicine, and even the automotive sector, are just some examples of enterprises that are taking advantage of micro-manufacturing technologies. Within this framework, the need to adapt the knowledge of macro-scale manufacturing processes to micro-scale is evident. This paper evaluates, through theoretical principles and experimental work, the machine-tool motion accuracy of a medium machining centre specializing in the micro-milling of elliptical cavities on aluminium workpieces. Measurements were taken to evaluate: deviations and/or errors in geometric accuracy, and the geometric quality errors caused by motion control and control software. The results show that, due to the structure and inertia of the machine tool, acceleration and deceleration do indeed affect the accuracy and quality of the micro-part. Furthermore, errors from motion control and/or control software are present because differences in the moving carriages create instabilities.