Search

A high performance composite grinding wheel with brazed diamond sheets was developed for rail grinding. The rotation stress formula of the composite grinding wheel is deduced and analyzed, and the cutting off effect of the brazing sheet on the resin in the composite grinding wheel is analyzed. The finite element simulation analysis of the rotation performance of the composite grinding wheel is carried out when the brazing sheet is in the middle of the grinding wheel or one end of the brazing sheet is flush with the grinding end of the grinding wheel. The corresponding composite grinding wheel is made to carry on the rotation test, which is compared with the simulation analysis results. The results show that for the O260-size rail grinding composite grinding wheel, when using 15 mm wide and 55 mm long brazing sheets, the optimal placement angle is 55°, followed by 60° and 45°. The analysis of the noise detection results of the rotary testing machine shows that the resonance speed of the rail grinding wheel is between 4600–4800 rpm, and the rotary noise of the composite grinding wheel with brazing sheet is lower than that of the resin grinding wheel.

Applying complex groove with variable helical angle, rake angle, core radius or groove width along tool axis is an essential way to improve the cutting performance of solid end mills. However, the usage of complex groove is limited due to the lack of an effective way to calculate wheel path for its machining, because the previous envelope theory or trial-and-error method that used for simple constant groove can no longer be used for complex groove. In this paper, a general model is established to calculate the wheel path for complex groove machining based on a mathematical optimization model, which have three constraints and one objective. First, the complex groove is defined by four curves, namely the edge curve, rake curve, core curve and flank curve, so that the variable helical angle, rake angle, core radius and groove width can be expressed by mathematical formulas. Second, the grinding wheel path is expressed as a series of its position vectors, including three location parameters and three posture parameters. Then, these vectors are calculated by searching the minimum machining error of groove width with three constraints: contact constraint to meet the rake and core radius requirements, groove width constraint to prevent the overcut with the adjacent edge and non-interfere constraint to prohibit the interfere with the current edge. Finally, the accuracy and efficiency of the model are validated by five experiments with different designed complex grooves.

Online relative location measurement of spatial geometric features is necessary for the high-precision manufacturing of long rotating parts. However, existing methods are imperfect because they are limited by the rotation state of the measured object or the measurement allowable space. To solve these problems, this study proposes a robust online measurement approach based on angle and size transfer, size transfer and analytical geometry theories. A polyhedral prism is used to synchronously calibrate the zero position of the laser displacement sensor, then a geometric model of the rotation angle corresponding to the sensor displacement change is established. Using only the displacement data, the 3-D relative location of multiple geometric features on different parallel planes is deduced by analytical geometry theory. The phase angle measurement of a diesel engine camshaft was used to verify the method. The results show that the method has high measurement precision, good stability and high efficiency.

Searching for and adjusting to the appropriate wheel positions for designed grooves are among the key issues in the manufacturing of the end mill, drill and other integral cutting tools. Along with the increasing requirements of product categories and quality, a large number of non-traditional and customized grooves continuously appear. However, as multivariable, nonlinear and multiple target problems, it is difficult to obtain the desired wheel position. Therefore, we introduce an intelligent method to search for the optimum wheel position for the designed groove with the known wheel geometry. According to practice, the basic parameters of the groove and wheel geometries are introduced, and the problems studied in this paper are explained. As a foundation, a robust algorithm is built to predict machined grooves with a series of equal distribution points and three parameters: the rake angle, core radius and groove width. The influence that the wheel positions have on groove geometries is then analyzed. Then, an objective function considering different machining requirements is built, and the optimum wheel positions are searched for while the function is solved. Furthermore, an enhanced niche particle swarm optimization (NPSO) algorithm is developed to solve the problem. Finally, 6 experiments are carried out to verify and analyze the algorithm. The results show that the algorithm can effectively find the desired wheel positions according to different machining precision requirements.

For shafts with a large ratio of length to diameter, the existing measurement method mainly uses a contact coordinate machine. But machining errors have a strong influence on the offline measurement results, and the accumulation errors of the measurement system also make the measurement datum difficult to identify. For this reason, a new on-machine measuring method is proposed based on the spatial analytical geometry theory to achieve the measurement of the shape and position tolerance of shafts. Through the method, the measurement system combines the line laser measuring instrument and the laser displacement sensor together. Then, the ideal central axis of the workpieces can be obtained and serve as a datum. Finally, the on-machine non-contact measurement of large-size shafts with geometric errors is realized with high measurement accuracy (

Helical groove geometry has important influence on the performance of end mills. It is the hardest and most time-consuming grinding process in end mill manufacture. This paper reports a graphical analysis method to obtain the structure parameters and geometric shapes of helical grooves with the known wheel geometry and position. Mathematical models are presented to describe the wheel geometry and position (including orientation and location) in space. A family of wheel surfaces is calculated and a scattered point set in the cross section plane is deduced according to the grinding path. Finally, an original algorithm for the cross sectional outline profile identification is given using graphical method. To verify this method, a calculation program programmed using MATLAB programming is developed. This study provides a fundamental understanding for the groove grinding process, based on this, the influence of different grinding process parameters on groove geometry (including radial rake angle, groove width and core radius) is discussed.