Non-contact, bi-directional tool tip vibration measurement in CNC milling machines with a single optical sensor
Non-contact, bi-directional tool tip vibration measurement in CNC milling machines with a single optical sensor
复制标题
DOI：
10.1016/j.ymssp.2020.106647
复制
发表时间：
2020-05
影响因子：
8.4
通讯作者：
Haoyang Zhang;Damian Anders;Michael Löser;S. Ihlenfeldt;J. Czarske;R. Kuschmierz
中科院分区：
文献类型：
--
作者：
Haoyang Zhang;Damian Anders;Michael Löser;S. Ihlenfeldt;J. Czarske;R. Kuschmierz
刀具的振动测量对于机械建模、易出错状态识别和机械操作优化具有重要意义。在铣削加工过程中，受迫振动是导致加工工件形状偏差和表面粗糙度的主要因素，并取决于主轴转速和刀具性能。预测机器系统动态行为的数值模型有助于减少振动。对于优化，模型参数需要通过同时测量在力的方向和它的垂直方向上的不同的旋转速度下的振动的工具尖端进行评估，具有高的时空分辨率。在这项工作中，一个非接触式，单传感器系统和信号处理算法的测量内的数控铣床与已知的力的振动行为。它可以直接在刀尖上进行现场同步双向振动测量，测量速率高达50 kHz，周向分辨率低于230 μm，位移不确定度低至40 nm，转速高达300 Hz。工具的动态行为参数进行评估，根据测得的振动频谱与相对不确定度为10-2，使模型优化。测量结果表明，随着主轴转速的增加，固有频率降低。虽然基于激光的测量原理不偏置振动行为，但它也固有地保证了感测轴的正交性。
Vibration measurements of tools are significant for machine modelling, error prone state identification and machine operation optimization. In the milling process, forced vibrations are the main factor resulting in shape deviations as well surface roughness of machined work pieces and depend on the spindle speed and tool properties. Numerical models for predicting the dynamic behavior of machine systems can help to reduce vibrations. For an optimization, the model parameters need to be evaluated by simultaneously measuring the vibration of the tool tip in force direction and its vertical direction under different rotational speeds with high spatio-temporal resolution. In this work, a non-contact, single-sensor system and a signal processing algorithm are presented for measuring the vibrational behavior inside of a CNC milling machine with a known force. It enables in situ, simultaneous bi-directional vibration measurements directly at the tool tip with measurement rates up to 50 kHz, a circumferential resolution below 230 μm and a displacement uncertainty down to 40 nm, at rotational speeds up to 300 Hz. The dynamic behavior parameters of the tool are evaluated depending on the measured vibration spectrum with relative uncertainties of 10-2, enabling model optimizations. The measurements show a decrease of the natural frequency with increasing spindle speed. While the laser-based measurement principle does not bias the vibrational behavior it inherently guarantees orthogonality of the sensing axes, as well.