Dressing Of Superabrasive Grinding Wheel Based On WEDD Processing System And Experimental Research

Metal-based diamond grinding wheels are more and more widely used in the grinding of hard and brittle materials due to their high bonding strength,good formability and long service life.With the long-term use of the grinding wheel,the dullness and falling off of the diamond abrasive particles have become inevitable problems,so the dressing demand of the grinding wheel is also increasing.As a precision grinding tool,the diamond grinding wheel has higher requirements for its own manufacturing precision,and also puts forward higher requirements for the dressing of the grinding wheel.In order to realize the high-precision dressing of the grinding wheel,the research and development of the grinding wheel dressing system is carried out in this paper.The details are as follows:According to the high-precision requirements of grinding wheel dressing and complex contour processing requirements,the grinding wheel dressing device is built,and the highprecision air-floating spindle system is used to provide high-precision rotary motion of the grinding wheel,and the wire electrode space attitude adjustment and fixed wire electrode guidance are designed.The discharge area machining structure.After testing,the rotation accuracy of the fixed shaft of the grinding wheel can reach 3μm;under the commonly used wire speed of 90mm/s,the wire runout can be reduced by about 64.7%.In addition,based on the contour approximation method,the contour shaping process of WEDM is compared and analyzed.When WEDM is used to shape large-replacement rotating parts,the processing efficiency of the multiple method is higher.In order to realize the breakdown of large discharge gap,avoid the concentration of pulse energy and formulate the servo strategy,the pulse power system is designed based on the high and low voltage composite technology,and the field programmable gate array(FPGA)chip is used as the basis.,a discharge state detection system is designed.Based on the power supply system,the influence of electrical machining parameters on the discharge gap was explored,and it was concluded that the pulse width and high and low voltage values had a greater impact on the discharge gap,and the change of the number of power tubes had a small impact on the discharge gap.With the increase of the high voltage value,the maximum increase of the discharge gap can reach 124%;with the increase of the pulse width,the maximum discharge gap can reach 200μm.Based on the discharge state detection system,the experimental verification of the machining state of the rotating and non-rotating parts was carried out,and it was found that the single pulse discharge frequency played a key role in the distribution of the discharge state.Based on the graphitization of diamond abrasive grains in WEDD,the selection range of processing parameters in actual processing is determined through simulation analysis.The simulation results show that for the dressing of diamond grinding wheels with a particle size of80 μm,the safer processing parameter is pulse width.10～20μs,current 20 A,speed above1000 rpm.According to the roughness of diamond grinding wheel grinding glass material,the change of surface roughness of grinding wheel grinding workpiece before and after dressing is compared and analyzed.The results show that the roughness of the workpiece is reduced by about 25% with the grinding wheel after dressing compared with the grinding wheel before dressing,which shows that WEDD can play a dressing effect on the worn grinding wheel.Based on the WEDD system,the machining of the inner groove profile of the diamond grinding wheel is completed;with the increase of dressing time,the height of the diamond abrasive grains increases gradually,from 17.9 μm to 69.1 μm.To sum up,the developed WEDD system can realize high-precision dressing of metalbased diamond grinding wheels,providing theoretical guidance and technical support for grinding wheel dressing.