Development of an optical probe for evaluation of tool edge geometry
Development of an optical probe for evaluation of tool edge geometry
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DOI：
10.1299/jamdsm.2014jamdsm0063
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发表时间：
2014
影响因子：
0.9
通讯作者：
S. Jang;Y. Shimizu;S. Ito;W. Gao
中科院分区：
文献类型：
--
作者：
S. Jang;Y. Shimizu;S. Ito;W. Gao
本文提出了一种用于评估刀刃几何形状的非接触式机上测量方法。在所提出的方法中，直径为几微米的聚焦激光束在工具边缘上留下痕迹。利用绕过刀具前刀面的激光束的光强度，可以获得聚焦激光束的光轴中心与刀刃之间的间隙。通过结合测量的间隙和聚焦激光束的 XY 位置信息，可以评估刀刃轮廓。在所提出的方法中，光源发射的激光功率的稳定性会影响刀刃轮廓的测量精度。因此，评估系统采用了改进的光学设计，以便可以实时补偿激光功率漂移和共模噪声的影响。开发了一种改进的评估系统，由激光二极管、分束器、一对透镜和两个光电二极管组成。通过实验来测试改进的光学设计所开发的评估系统的基本性能。还讨论了刀刃轮廓评估中测量误差的可能来源。此外，还进行了计算机模拟，以确认所开发系统沿刀刃轮廓的测量分辨率。扫描时，使用示波器分别测量P M 和P R 的输出电压信号V M 和V R ，示波器的数据采集由函数发生器的数字信号触发，以保证测量仪器的数据采集与激光束扫描之间的同步。通过使用获取的输出电压信号，方程中的参数q。导出式(2)，并换算为聚焦激光束位置相对于刀刃轮廓的偏差δ。利用δ 获取刀刃轮廓数据。考虑扫描路径的极坐标转换和变化δ，通过最小二乘法定义圆角边缘的中心点。当扫描路径在测量范围内偏离测量目标时，两个结果没有表现出很好的一致性。
This paper proposes a non-contact and on-machine measurement method for evaluating tool edge geometry. In the proposed method, a focused laser beam having a diameter of several micrometres traces over the tool edge. By utilizing a light intensity of the laser beam passed around the tool rake face, the gap between the centre of the optical axis of the focused laser beam and the tool edge can be obtained. By combining the measured gap and the information on the XY positions of the focused laser beam, the tool edge contour can be evaluated. In the proposed method, stability of the laser power emitted from a light source would affect measurement accuracy of the tool edge contour. A modified optical design was therefore applied to the evaluation system so that a laser power drift and influences of common-mode noise could be compensated in real time. A modified evaluation system consisting of a laser diode, a beam splitter, a pair of lenses and two photodiodes was developed. Experiments were carried out to test the basic performances of the developed evaluation system with the modified optical design. Possible sources of measurement errors in the tool edge contour evaluation were also discussed. Furthermore, computer simulation was carried out to confirm measurement resolution of the developed system along the tool edge contour. scanning, output voltage signals V M and V R from PD M and PD R , respectively, were measured by using the oscilloscope, whose data acquisition was triggered by a digital signal from the function generator to assure the synchronization between the data acquisition of the measurement instrument and the laser beam scanning. By using the acquired output voltage signals, the parameter q in Eq. (2) was derived, and was converted into the deviation of the focused laser beam position δ with respect to the tool edge contour. By using δ , data of the tool edge contour was acquired. The center point of the rounded edge was defined by least-squares method considering polar coordinates conversion of the scanning paths and variation δ . The two results did not show good agreement when the scanning path was deviated from measurement target over the measurement range.