Optimization of micro milling processes through controlled vibration of workpiece

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Micro milling for die and mould fabrication is a well-established manufacturing process. An increasing utilization for medical and biotechnical components and applications can be stated. Compared to other micro manufacturing processes such as laser ablation or electrical discharge machining (EDM) it is characterized by high flexibility for work piece shapes and low process time. The process performance is mainly limited by the work pieces hardness and the according tool wear. Also, ploughing effects at very small chipping thickness have negative effects on the process result. Premature tool breakage and bad surface roughness are the consequences. This research project aims to a process optimization by implementing an auxiliary device for vibration assisted micro milling. The work piece is excited in two directions horizontally to the spindle axis. Frequency, amplitude and phase shift of the actuator oscillation are controlled according to the rotational angle of the machine tool spindle. Therefore a real time environment is connected to the actuator integrated work piece support as well as to the control system of the machine tool. By varying the oscillation signals different process conditions can be set systematically. Process results are investigated in terms of achievable surface roughness, tool wear and surface topography. The experimental verifications are accompanied by modelling the resulting cutting edge trajectories. By that, reproducible surface structuring by micro milling can be enabled.