Papers by Author: Ling Ye Kong

Abstract: It is an important method to machine revolution aspheric with Arc Envelope Grinding Method（AEGM）. CNC system controls the feed rate of the arc center of the end of the wheel in grinding, Disk-shaped grinding wheel processing curve (ie, cross-section curve of rotary aspheric) and motion curve of the arc center of the wheel are equidistant curves each other . Based on the analysis of the angular velocity (ω) of the grinding point, the relationship between the feed rate of the arc of the wheel (υ0) and the feed rate of the grinding point (υ) is analyzed, the feed rate and the angular velocity of the grind point is discussed when the eccentricity of the meridional cross-section curve take different values. The results show: 1) the feed rate of the grinding pointυ=υ0±ωr; 2)ω is changing in grinding, When the caliber of axisymmetric aspheric (ie, z value) is small, ω will change slowly, otherwise, ω will change rapidly when the caliber of axisymmetric aspheric is large; 3) the ratio of υ/υ0 will change with the z-axis coordinate changes. υ/υ0is larger when the caliber of axisymmetric aspheric is smaller. By analyzing ,υ/υ0 and other parameters, the motion law of the wheel is obtained, which will provide confirm base for optimizing feed rate in grinding and improve the precision of grinding.

Abstract: It is an important method to machine revolution aspheric with Arc Envelope Grinding Method（AEGM）. In this article, the relationship between the grinding point of the wheel and its position is analyzed, and motion law of the grinding point is discussed in grinding aspheric. According to motion velocity of the grinding point , the concrete position of severe wear for the wheel can be calculated out theoretically. It is possible to achieve even angular velocity of the grinding point by adjusting the wheel feed rate, so the angular velocity of wheel movement is optimized, which provide confirm base for improving the precision of grinding aspheric.

Abstract: A new planarization grinding method based on the cluster magnetorheological (MR) effect is presented to grind optical glass in this paper. Some process experiments were conducted to reveal the influence of the speed of the grinding disc and grinding time and grinding pressure during the machining process. The results indicate that the speed of the grinding disc influences definitively on grinding effect of this planarization grinding method based on the cluster MR-effect. When the speed of the grinding disc is 110r/min, better machining effect can be achieved. Furthermore, the influence of the grinding time on machining effect is obviously, and the proper machining time is 6mins. However, under the experiment condition in this paper, the influence of grinding pressure on machining effect is unobvious.

Abstract: Based on the principle of MR polishing processing, cluster MR-effect polishing method which formed by cluster distributed magnetic body has been put forward in this article. The author analyzed the principle of the cluster MR-effect plane polishing, developed experimental device and conducted processing experiment to K9 optical glass and silicon slice. Results show that the method is feasible and can realize high precision polishing. The surface roughness of K9 glass and silicon slice can achieve respectively Ra0.005µm and Ra0.016µm finally after processed. It has high efficiency at the same time, the surface roughness can decrease 1 order of magnitude after processed 10 minutes, the surface roughness of K9 glass and silicon slice can realize respectively decrease 3 orders of magnitude and 1 order of magnitude after processed 50 minutes.

Abstract: To improve the effect of magnetorheological finishing (MRF), it is necessary to control the behavior of abrasive particle effectively in machining process. This article described the machining principle of semi-bond abrasives under the MR effect, then, analyzed the magnetic field of the polishing tool. Based on the magnetic field theory, the constrained model of abrasive particle was established, consequently, the force and the machining behavior of abrasive particle were analyzed. And an experiment was carried out to analyze the effect of the abrasive behavior on the material removal. The results show that the experimental results are identical with the theoretical analysis. Therefore, the control of the particle behavior in process is proved to be available.

Abstract: Based on the analysis of the machining process of magnetorheological finishing with the tiny-grinding wheel cluster, the motion model of abrasive in the tiny-grinding wheel cluster was proposed to describe the motion trajectory and the dwell time of abrasive relative to the surface of workpiece. Then, the experiment was applied to study the effects of the motion trajectory and the dwell time on surface quality and machining efficiency of the workpiece. According to the analysis, a method to improve surface quality and machining efficiency in MRF with the tiny-grinding wheel cluster was presented.

Abstract: When grinding the revolving curved surface with Arc Envelope Grinding Method, the different curvatures in the convex and concave surfaces make a great difference in the surface roughness. In order to solve this problem, the relationship among envelope height, feeding rate, rotational speed and curvature of workpiece was analyzed based on equal-envelope-height grinding method. The results presented that, low feeding rate of grinding wheel and high rotational speed of workpiece were helpful to obtain smaller envelope height. And the smaller the radius of workpiece curvature, the more different the surface roughness. Besides, it was an effective method to solve this problem by changing feeding rate. The feeding rate should be changed directly proportionally to radius of workpiece curvature. Then, the experimental results indicate that, the fluctuation ratio of surface roughness with variable feeding rate is reduced to 4.896% from 26.17% with constant feeding rate. It proves the validity of hypothesis.

Abstract: Revolving curved surface of mould should have low roughness as well as high accuracy of geometry profile. And it is an essential method to meet the accuracy request with grinding process. In order to solve the problem of grinding such revolving curved surface, an Arc Envelope Grinding Method (AEGM) is presented in this paper, which uses a wheel with arc section. By analyzing the movement of the grinding point, the relationship between the length of trajectory that the grinding point moves along and radius of the arc, curvature of workpiece is explained. Meanwhile, the relationship between the radius of arc, the curvature and the grinding area is studied.

Abstract: Large-scale surface such as mould should have low roughness as well as high accuracy of geometry profile. And it is an essential method to reach the accuracy request with grinding process. In this research, due to the variety of geometry profiles, an Arc Envelope Grinding Method (AEGM) is presented, the difficult problem of grinding large-scale revolution surface can be solved. Meanwhile, the grinding wheel dressing and its shape precision are the keys to the precision of revolution surface in the grinding with AEGM. In this paper, the influences of setting error of diamond point dresser, which dress the grinding wheel into an arc section by using numerical control function of NC grinding machine, upon the shape accuracy of plate-shaped grinding are analyzed. It is shown that shape error of the grinding wheel increases with the increases of dresser setting error in diameter direction, radius of tip arc on the grinding wheel, while it reduces with the increase of radius of the grinding wheel, and shape error distributes no uniformly but symmetrically along axial direction.

Abstract: The profile accuracy of the workpiece is mainly determined by the accuracy of abrasive wheel in the form-grinding process. Thus, the shaped wheel dressing becomes one of the key points in the form-grinding process. In order to grind the revolving curved surfaces grooves whose cross-sectional profiles are steep and smooth, a new NC dresser with three NC axes is developed by adding a swing axis on the basis of NC external cylindrical grinding machine. A wheel of any desired convex profile can be dressed when using the Diaform single-diamond dresser and the possible geometrical interference between the single-diamond dresser and wheel can be eliminated. By analyzing the influence of installation accuracy on the profile accuracy, a method of comprehensive error compensation is presented. The comprehensive errors can be diminished greatly to improve the profile accuracy by means of error compensation. It is proved in the experiments that the precision requirements of grinding the formed surfaces grooves can be met.