Research On Dressing Precision Of EDM For Super-hard Grinding Wheel

With the promotion of the use of super-hard molded grinding wheel in the hard and brittle processing and precision manufacturing,the technology of ultra-hard grinding wheel by EDM has also been gradually taken into account.In particular,the demand for shaping precision growth of molded wheel is becoming increasingly urgent.The generatrix profile and roundness of grinding wheels are important parameters to measure the dressing precision of the forming grinding wheel.Therefore,the copying process from the profile of the electrode busbar to the profile of the grinding wheel generatrix has become the core of research.Based on the CNC grinding wheel dressing platform,the cylindrical copper-tungsten electrode was used to dress the diamond grinding wheel.The electrode is corroded during the discharge dressing of the diamond grinding wheel,which poses difficulties in dressing the wheel.Therefore the concept of loss ratio was introduced to quantitatively analyze the influence factor of current,voltage,pulse width and rotation speed and its influence on the corrosion of electrode generatrix are analyzed.It provides a theoretical basis for maintaining the shape of the electrode during wheel dressing.According to changed the experimental parameters,the influences of rounding of EDM diamond grinding wheel were studied and the standard deviation between the pulsation and the surface fluctuation of the grinding wheel was calculated by the on-line measuring,which summed up the influence of the current under the rotation of the electrode.In the study of grinding wheel generatrix,the dressing effect of grinding wheel generatrix is indirectly reflected by measuring the profile of the grinding groove,which summarize the influence of grinding wheel dressing effect.According to record the coordinates of the machine during discharge dressing,the influences of discharge distance were discussed,which caculated the formula of the discharge distance and was verified with different grain of grinding wheels.The surface shape of different size grinding wheel after dressing was observed by electron microscope,Intuitively determine the condition of the diamond on the surface of the wheel and the dressing effect.The experiment rule of cylindrical grinding wheel was applied to the dressing of the conical grinding wheel.The edge of the grinding wheel,the electrode and the wheel of the grinding wheel were measured.The results showed that the slope of the generatrix after the trimming was approximately parallel and the jitter was greatly reduced.Dressing effect is better.