Papers by Keyword: On-Machine Measurement (OMM)

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Authors: Hao Huang, Xiang Yang Lei, Jian Wang, Qiao Xu, Liang Yu He, Yin Biao Guo
Abstract: The causes of machining errors are very complicated and apt to mutual influence in aspheric grinding, so it is difficult to improve machining accuracy by control one cause. To compensate the machining error of large aspheric grinding, an error-compensation technique using on-machine profile measurement system in three axes grinding machine are presented. To verify the effectiveness of the compensation machining and the reliability of the measurement system, experiments on high-precision grinding machine were performed. Moreover, the compensation machining with the on-machine measurement substantially decreases the machining errors and improve machining accuracy by more than 45%, compared with the non-compensation machining.
Authors: Sheng Bao, Ping Fa Feng
Abstract: The On-machine measurement is usually based on the data of points. When data come from the CNC machine tools, the information they carry may be invalid. Therefore, it is unsuitable to compensate the errors by rotating and translating all data. In this paper, a practical algorithm is proposed to compensate the errors. Firstly, the valid data are picked out and sorted according to their normal vectors. By using the least square method, an error reference frame is constructed. Then the relation between the compensation values and coordinates of the theoretical points is derived. Finally, an example of aircraft structural parts is presented to validate the design.
Authors: S.J. Han, J.K. Choi, Seok Woo Lee, Hon Jong Choi
Authors: Hitoshi Ohmori, Y. Watanabe, Wei Min Lin, Kazutoshi Katahira, T. Suzuki
Abstract: Ultraprecision optical components require ultra-fine smooth surface quality of sub-nanometer or sub-angstrom in Ra. To satisfy these requirements, ultraprecision on-machine measurement system is very important, by which the profile measurement and evaluation is conducted on the machine. The form accuracy is improved by compensating machining when the form accuracy is not enough. Ultraprecision on-machine measurement systems were developed for measurement with high-accuracy and high-efficiency. It was confirmed that the on-machine measurement with AFM was possible for surface roughness or complex form for local areas. In addition, a laser probe unit with a maximum resolution of 1nm, a measuring range of 10mm, a repeatability of 5.6nm and a maximum measurable angle of 60 degrees was developed. The possibility of the non-contact on-machine form measurement was confirmed for global form accuracy control.
Authors: X. Liu, Y. Gao, Suet To, Wing Bun Lee
Abstract: Lateral shear interferometers have large measurement range and good anti-disturbance ability. They have similar accuracy compared with the reference based interferometers. Based on a specially designed shear generator, a new lateral shear interferometer is proposed. The new system has a complete common optical path and a simple mechanism. The optical model of the interferometer is presented and the anti-vibration characteristics are analyzed. To validate its antivibration ability for on-machine surface measurement, experimental tests have been conducted and results presented.
Authors: G. Valiño, C.M. Suárez, J.C. Rico, B.J. Álvarez, D. Blanco
Abstract: The current requirements for an efficient dimensional inspection of manufactured parts have lead to development of different in process and on-machine measurement (OMM) techniques. Touch trigger probes (TTP) are the most common technologies utilized, inspired on contact probes used on coordinate measuring machines (CMMs). The on-machine accuracy of TTPs depends upon precision of the tool-machine control as well as upon the procedure for TTP presetting. Taking this into account, a different OMM technique is considered in this work, which consists on a laser micrometer (LM) that is commonly used for in-process measurement of continuous products. The behaviour of TTP and LM is analysed and discussed in terms of repeatability and reproducibility. Results obtained by both techniques are compared each other by measuring a cylindrical workpiece and by checking the results with those obtained on a CMM.
Authors: Ryo Kobayashi, Shinya MORITA, Y. Watanabe, Y. Uehara, W. Lin, T. Mishima, Hitoshi Ohmori
Abstract: A non-contact on-machine measurement system has been developed since various precise machines are getting lighter and smaller; therefore, processing with nano-precision is demanded recently. This system makes possible to measure with high precision without any damages and it is unnecessary for workpieces to attach or detach from a machine tool. Moreover, this system achieves on-machine form error compensation with high precision. On the other hand, the details of the system performances are still unknown. This study focuses on evaluating the performances by the comparison of the results that measured by this system and an existing measurement instrument under various conditions. As a result, this system shows an equivalent capability of measurement with high precision as the existing measurement instrument.
Authors: Y. Watanabe, Sei Moriyasu, Kazutoshi Katahira, Wei Min Lin, Hitoshi Ohmori, Akitake Makinouchi, Hirofumi Tashiro
Authors: Zhong Ren Wang, Yan Hua Wu, Yan Ming Quan
Abstract: A novel movable monocular stereo vision measurement system was designed considering the application objectives and on-machine measurement situation. The physical model and mathematical model for measurement accuracy was established. The appropriate structure parameters scope was obtained after simulation analysis. Finally, an application example of the measurement system is introduced.
Authors: Peng Yao, Takeshi Matsuda, Tian Feng Zhou, Ji Wang Yan, Tunemoto Kuriyagawa, Ya Dong Gong
Abstract: On-machine measurement and statistical analysis of wheel topography are important for real-time monitoring the wheel condition during grinding and predicting the performance of grinding process. In this paper, the surface topographies of grinding wheel in the different stages of the grinding of fused silica and BK7weremeasured with a white light interferometer, which was set on the surface grinder. Height parameters of 3D surface roughness were proposed to evaluate the wheel wear. Wheel wear mechanisms were essentially determined by analyzing the different material removal modes of optical glasses. Grinding of BK7 mainly causes severe attritious wear of grains, while grinding fused silica, self-sharpening effect makes grinding sustain for a long time.
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