【作者】 许明明；

【导师】 胡德金； 裴景玉；

【作者基本信息】 上海交通大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 基于在光学投影或者机器视觉的精密曲线磨床中，不能使用工作液，同时其砂轮的机械修整力不能过大，否则会引起砂轮变形。对此，本文提出了雾状介质（雾状去离子水）电火花与机械复合修整非金属基金刚石砂轮方法。该方法是一种特种加工法与传统机械修整法有机结合起来的新型金刚石砂轮修整技术，采用雾状介质减少了对液体电介质的依赖，而且独特的结构设计大大降低了修整过程中的机械修整力和修整工具的损耗。针对电火花加工技术和非导电结合剂金刚石砂轮的特点，采用砂轮表面涂覆导电材料建立电火花放电的条件，使电火花修整非导电金刚石砂轮成为了可能。本文以树脂基金刚石砂轮为研究对象，开展和完成了如下的研究工作：（1）针对树脂结合剂的非导电性，使用表面涂覆导电性材料建立辅助放电条件，实验对比分析了砂轮表面涂覆不同辅助导电材料后的修整效果，得出砂轮表面涂覆石墨粉末具有最佳的修整效果，并实验研究了涂覆工艺，使涂覆后的砂轮具有理想的导电性能，同时也不会使石墨损耗率过大。其次，分析了雾状介质中放电加工的特点，理论推导和实验得出雾状介质中放电加工的放电间隙比液体介质和空气介质中大，则雾状介质放电有利于提高放电稳定性。最后，建立了复合修整过程中电极损耗模型。（2）建立了电火花放电机械复合修整树脂基金刚石砂轮理论模型，采用有限元分析软件ANSYS进行了温度模拟分析，以环氧树脂为例，分析在高温条件下金刚石笔去除树脂结合剂的特性。并通过对理论模型分析和仿真研究，得到了不同修整参数对修整效果的影响规律，为后续树脂结合剂金刚石砂轮的修整实验研究奠定了基础。（3）在复合修整金刚石砂轮理论分析基础上，进行了雾状介质电火花与机械复合修整树脂基金刚石砂轮实验。实验研究了极性效应、放电峰值电流、脉冲宽度等修整参数对修整后砂轮表面微观形貌，金刚石笔损耗和修整后砂轮磨削性能的影响。并对比研究了修整前后砂轮磨削工件表面粗糙度和微观形貌，修整后的砂轮磨削工件表面微观纹理均匀，没有凹坑和裂纹且工件表面粗糙度较低。（4）横向对比研究了复合修整法、传统的机械修整法和电火花修整法修整后砂轮的表面微观形貌、砂轮的磨削性能和磨削工件表面的粗糙度，得到如下结论：雾状介质电火花机械复合修整法修整后的砂轮具有最佳的表面微观形貌和砂轮的磨削性能，机械修整法修整后的砂轮效果最差，这三种修整方法对降低工件表面粗糙度方面无太大差距。更多还原

【Abstract】 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.更多还原