Mechanism Analysis & Experimental Research Of Dressing Resin-bond Diamond Grinding Wheels With Electric Discharge Machining

The super-abrasive diamond grinding wheel is widely used in the finishing and super-finishing process of manufacturing products with hard or super-hard materials. But there exists some problems which can have bad effects on the grinding process such as the distortion of the grinding wheel, generating the self-vibration force and losing the scrap-containing space as the wheel's lacking the self-dressing ability. These problems will seriously weak the stability and lower the efficiency of the grinding process. So it's necessary to research the truing and dressing method of the grinding wheel. According to the properties of the non-electric grinding wheel, like the resin-bond diamond grinding wheel, a method that constructs the electric conditions through laying electric materials on the surface of a non-electric wheel makes it possible to use EDM to dress the non-electric grinding wheel in this paper. It can widen the range of EDM used on truing and dressing grinding wheel.Firstly, the theories of material removal mechanism in the EDM are introduced. There are three states in an EDM process: the formation of discharge channel, the distribution and transfer of the discharge energy on the electrode, the wiping off the removal material from the wheel's surface. Then, the feasibility of dressing resin-bond diamond grinding wheel by EDM is illuminated by comparing with the property differences between diamond and resin. Secondly, the author uses ANSYS software to simulate the temperature field's distribution on the surface of the grinding wheel where discharge happens on. The regulation with the distribution and transformation of the temperature field during the EDM dressing process has been recognized. The simulation result show that the suitable discharge current for dressing resin-bond grinding wheel is 1A～5A; the thermal influence area and temperature is gradually increasing along with the discharge current's increasing; the discharge impulse length has little impact on temperature field transformation and only influences the area of the thermal field. All that have been done are to provide the reference parameters for real EDM dressing experiments on grinding wheel.In the real dressing experiments, it focuses on the impacts of different discharge parameters and conditions. It mainly dressed the non-electrical grinding wheel like resin-bond diamond grinding wheel by means of covering the wheel's surface with electric materials such as carbon powder. The dressing experiments'results account for that EDM can be used on dressing non-electrical grinding wheel. The copper dressing electrode is preferred to plumbago one as it will result in unstable discharge between the two electrodes. The dressing result is comparatively better when using the solid electronic materials to cover the wheel's surface than using the liquid one. The discharge current is the most important factor which would have significant influence on the dressing result of the grinding wheel, the most suitable range of discharge current in dressing resin-bond diamond grinding wheel is 1A～4A. The discharge impulse length also has a little impact on the wheel's surface topographty, but this factor is not so important as discharge current. The discharge voltage has little effect on the dressing quality and efficiency, but the lower voltage will cause arc discharge and collision between the two electrodes.