Research On On-machine Electrical-discharge Dressing Device And Dressing For Metal-bonded Grinding Wheels

Metal-bonded diamond grinding wheels are widely used in precision and ultra-precision grinding of hard and brittle materials,high speed and high efficiency grinding.However the metal-bonded diamond grinding wheels also has the disadvantages of easy blockage,poor self-sharpening.In the grinding process,the diamond abrasive will gradually be blunted and chip space will gradually decrease due to the effect of high grinding force and temperature.The outer circle contour of grinding wheel became uneven wear and gradually lost its original contour and accuracy which will result low processing efficiency and machining precision.So it is necessary to be dressing after grinding for a certain time.Compared with traditional dressing methods,electro?discharge dressing,as a non-contact dressing technique,has the advantages of no contact force,high dressing efficiency,low cost,easy to implement.Aiming at off-line dressing of metal-bonded diamond grinding wheel by electro-discharge method at present,an on-machine electro-discharge dressing device is developed and electro-discharge dressing experiment is studied,and the main research works are following:Based on mechanism of electro-discharge dressing,an on-machine device for electro-discharge dressing of metal-bonded diamond grinding wheel is designed,the layout of XYZ axes with CNC control orthogonal,and electrode is amounted on end of Z axis which could realize automatic control of dressing complex contour of grinding wheel.Grinding and dressing are carried out on the same wheel arrange at once,and the dressing efficiency and dressing accuracy are improved.The abrasive's morphology of grinding wheel after electro-discharge dressing is experimentally studied,The effect of electro-discharge dressing parameters,such as discharge voltage,peak current and pulse on-time,on distribution of abrasive's density and height on wheel's surface are analyzed.The particle swarm optimization algorithm(PSO)is applied to the optimization of electro-discharge dressing parameters,and objective function of abrasive's density and height is set up.Electro-discharge dressing parameters could be optimized based on a few groups of electro-discharge dressing experiment results,then dressing experiment is carried out using optimized parameters by PSO,and better dressing effect is obtained.