Optimization of micro milling processes through controlled vibration of workpiece

用于模具制造的微细铣削是一种成熟的制造工艺。可以说，医疗和生物技术组件和应用的利用率越来越高。与激光烧蚀、电火花加工等其他微细加工工艺相比，它具有加工时间短、零件形状柔韧性高等特点。工艺性能主要受工件硬度和相应刀具磨损的限制。此外，在很小的切屑厚度下的犁削效应对工艺结果也有负面影响。造成的后果是刀具过早破损和表面粗糙度差。本研究项目旨在通过实现振动辅助微细粉碎的辅助装置来进行工艺优化。在与主轴轴线水平方向的两个方向上激励工作件。根据机床主轴的转角控制执行器振荡的频率、幅值和相移。因此，实时环境被连接到致动器集成的工件支撑件以及机床的控制系统。通过改变振荡信号，可以系统地设置不同的工艺条件。根据可实现的表面粗糙度、刀具磨损和表面形貌对工艺结果进行了研究。在进行实验验证的同时，还对由此产生的尖端轨迹进行了建模。通过这一点，可以通过微磨削来实现可重复的表面结构。

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.