Papers by Author: Yu Mei Luo

Abstract: This paper deals with an on-line mismachining error measurement for curve grinding based on digital image processing. Using CCD camera, the contour of the workpiece’s finished surface is captured and the image is preprocessed for denoising and edge detecting. The worktable is guided by the image of the finished workpiece to follow the path of the finished contour and then the real curve of the finished workpiece is measured by fitting a curve according to the moving path of the worktable. Finally, the machining error is obtained by comparing the measured curve with the theoretical curve of the workpiece. This method is applied to a CNC curve grinding machine MD9040. A measurement experiment is given. The experiment results show that the measurement method offers high detection precision and can be used in wide fields, especially for measuring the parts with complex curve.

Abstract: This paper deals with an application to automatic compensation of grinding wheel wear by an image processing based real-time measurement method in dry curve grinding. An online image measurement system was schemed out and its principle was introduced in detail. Real time image of workpiece and grinding wheel is grabbed by CCD camera during grinding process. For the purpose of increasing the measurement precision, a new sub-pixel level accuracy edge detection approach combining Zernike moments operator with Sobel operator is proposed for locating the edge of the machined workpiece, which has advantages of fast processing speed and high edge locating accuracy. The wear amount of the grinding wheel is calculated by the image processing software, and is compensated automatically by NC controller. Finally, this method is applied to a new type CNC curve grinding machine MD9040. The experimental results show that the measurement and compensation method proposed in this paper is effective, and the contour error of the workpiece with real-time compensation is less than the feeding resolution for a compensation of 2μm.

Abstract: In traditional NC curve grinding, the grinding wheel’s rotary surface is generally not on the grinding point’s normal direction, which will bring the distortion of grinding wheel and decrease the machining precision. This paper presents a new technology, which is called the non-interference normal tracking for NC curve grinding process. By controlling the worktable to rotate in the x-y plane, the superposition between the rotary surface of the grinding wheel and the normal vector of the workpiece’s contour is realized, and the interference between the wheel’s body and the workpiece could be avoided at the same time. A mathematic model is established and an algorithm to calculate the worktable’s rotary angle is proposed. Finally, the algorithm is applied in a new-type digital curve grinder successfully. The results show that the method is reliable and effective.

Abstract: Ceramic coating materials own some advantages, for example high-rigidity, good abradability and good performance under high temperature. At the same time, ceramic coating materials are also difficult-to-machine materials. High machining precision and efficiency can be obtained in grinding WC-Co coating by cup wheel. The affection of grinding temperature is very important for grinding processing. But there is no research on grinding temperature of WC-Co coating by cup wheel. So in this paper, grinding temperature by cup wheel is researched on theory, the new concept, which is effectiveness width of arc moving heat source, is presented, and theoretical formula of grinding temperature is also built. Then experimental research on grinding temperature of WC-Co coating by cup wheel is done by use of thermocouple temperature measurement technology. The experimental results show the validity and effectivity of the theoretical formula. The affection of grinding parameters to grinding temperature is researched also.