A Study On Near-Dry Electrical Discharge Dressing Non-Metal Bonded Diamond Grinding Wheel

This thesis proposes an effective dressing technique–near dry electrical dischargemechanical dressing (EDMD) on nonmetal bonded diamond wheel. This dressing technology isa non polluting truing and dressing method and has good application area for thetruing/dressing of precision grinding machines in the grinding industry. This method hasgood dressing effects and finishing quality, and dressing tools reduces greatly, andmechanical dressing force is small with optimized mechanical design. But, the resin hasweak conductivity ability, and a conductive phase is coated on the wheel surface toincrease the conductivity of the nonmetal bond. A resin bond diamond grinding wheelwas used in EDMD. The comments are made on this new dressing technique based on thetheoretical analysis and experimental observations.(1) The resin bond has weak conductivity ability, and a conductive phase is coatedon the wheel surface to increase the conductivity of the nonmetal bond. The differentcoating material was used to dress resin bond diamond grinding wheel, and it shows thatthe wheel surface coated graphite powder gets the best dressing result, and a coatedprocess of graphite powder was researched in order to get the best conductivity ability ofthe resin bond wheel. The characteristic of mist discharge medium was analyzed. It gotthe conclusion that the discharge gap in mist discharge medium is larger than air andliquid medium in the same discharge parameters. So, it has the best electrical dischargestability in mist medium. At last, the electrode wear model of spark was built.(2) The theory model of EDMD was researched to analyze feasibility and selectoptimized parameters. Finite element simulation software ANSYS is used to analyze thetemperature distribution. The removed characteristics of epoxy resin with diamonddresser were analyzed. It provides theory basis for EDMD experiment. (3) Electrical discharge mechanical dressing (EDMD) experiment was carried out on adie sinking electrical discharge machine. The influence of polar action, peak current,Pulse width, open voltage, wheel speed and diamond pen dressing depth were researchedto evaluate the dressing performance of EDMD in terms of surface morphology of thewheel surface, diamond pen wear, the grinding force workpiece roughness andmorphology of workpiece surface. It shows that the dressing parameters have importanteffect on dressing results. It also shows that better surface roughness was obtained, thetexture of workpiece surface uniform and workpiece surface is no pits and crack afterdressing.(4) Electrical discharge mechanical dressing method, electrical discharge dressingmethod and mechanical dressing method were compared of the wheel surface morphology,grinding force and workpiece roughness. The dressed wheel with multiple dressing hasthe best surface morphology and the smallest grinding force. The workpiece roughness isclose with this three dressing method.