【作者】 沈剑云；

【导师】 徐燕申； 徐西鹏；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2004， 博士

【摘要】 结构陶瓷材料因其优异的机械、热学等性能而被广泛应用于各个工业领域,显示出优良的适应性和广阔的应用前景。而陶瓷材料的难加工性使其磨削加工成本居高不下,对其磨削加工机理和先进加工工艺的研究一直是行业的热点课题。磨削温度直接影响砂轮寿命和工件加工质量,是磨削加工领域研究加工过程及其本质的重点。在结构陶瓷材料的磨削过程中,磨削温度可能造成金刚石磨粒石墨化、工件表面残余应力等各种形式的热损伤,从而严重影响金刚石砂轮的寿命和结构陶瓷零件的使用性能。本论文研究了不同材料性能的结构陶瓷材料在不同磨削方式情况下的磨削机理和磨削温度特征及磨削过程中的磨削热传输特性,通过对磨削过程中磨削热的产生和传递机制的分析,有针对性地采取增强冷却和润滑作用的磨削热抑制实验研究。通过对理论解析和实验结果的分析,探讨结构陶瓷磨削过程中磨削热的产生和传输特性以及有效解决磨削热造成工件或者砂轮热损伤问题的手段。研究结果表明,结构陶瓷磨削过程中材料以塑性变形和脆性断裂两种方式去除,而大部分磨削能量是消耗于金刚石磨粒与工件间的塑性滑擦耕犁过程,因此在较小的单颗磨粒切削厚度条件下和磨削延性相对较好的陶瓷材料时磨削比能较高,高的磨削比能使其必须消耗更多的磨削能量,并在磨削弧区砂轮与工件的接触界面上转化为磨削热,而结构陶瓷材料导热性能差和金刚石磨料 良好的热特性使得磨削热传入工件的比例降低,更多的磨削热通过金刚石磨粒来传递使得磨粒点上的温度大幅上升,并可能导致金刚石磨料热损伤及因树脂结合剂软化而产生非正常脱落;通过运用内 冷却方式可以使冷却液 更充分地进入磨削弧区从而带走更多的磨削热而起到更有效的冷却作用,降低磨削温度;而通过施加润滑剂可以减少磨具 表面上金刚石磨粒塑性滑擦耕犁工件过程中两者间的摩擦作用,从而降低了磨削过程中能量消耗,达到了抑制磨削热的目的。更多还原

【Abstract】 Structure ceramics are becoming popular materials for industrialcomponents, and grinding with diamond wheel has been widely used in theproduction of structure ceramics components. Virtually, all of the energyconsumed by grinding is essentially converted into heat distributingwithin the grinding zone. Concentrated heat input leads to temperaturerise on the surface of structure ceramics which may lead to thermaldamage to workpiece and grinding wheel. Therefore, it is necessary tostudy the characteristics of the grinding temperature and suppression ongrinding heat in grinding of structure ceramics. In this study, mechanism of ceramics grinding and characteristics ofgrinding temperature were evaluated with grinding forces andtemperature measurement in grinding of different ceramics under variousconditions. With the analysis of heat transfer during ceramics grinding,suppression methods of grinding heat with enhanced cooling andlubrication were presented to prevent thermal damage during the grindingprocess. The results indicated that most of the grinding energy must beexpended by ductile plowing, even though material removal is mainly bybrittle facture. Therefore, the specific grinding energy increases with thedecrease of material removal rate and grinding of ductile ceramic. Theconsumed energy is converted into heat distributing within the grindingzone where the ceramics interacts with the grinding wheel. Due to the lowthermal conductivity of structure ceramics and high thermal conductivityof diamond abrasive, most of grinding heat is transferred into diamondgrits and cause high tip temperature, which may lead to graphitization ofdiamond and softening of the resin bond. Adequately transporting coolantthrough the grinding zone or applying lubricant oil to suppress thefriction between the wheel and workpiece can effectively lower grindingtemperature.更多还原