【作者】 马宏路；

【导师】 陈根余；

【作者基本信息】 湖南大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 超硬磨料(金刚石和立方氮化硼)砂轮具有异常优良的磨削性能,在精密、超精密磨削,难加工材料成型,高效磨削和磨削自动化中有广泛的应用前景。由于超硬磨料砂轮本身特性,采用传统的基于力的修整方法修整超硬磨料砂轮很难达到使用要求,严重影响了超硬磨料砂轮优良磨削性能的充分发挥。基于热作用的新的激光修锐和整形方法的研究引起了各国学者的关注。本文分析激光修整超硬磨料砂轮的国内外研究现状,指出了现阶段激光修整超硬磨料砂轮的不足。提出了用声光调Q YAG脉冲激光修整超硬磨料砂轮的特点及优势。 从脉冲激光修整超硬磨料砂轮的机理出发,利用闭环控制单脉冲的输出,进行系统地青铜金刚石砂轮修整实验,得到了较好的修整结果,获得了各个激光参数对修整青铜金刚石砂轮的影响规律。 分析了单脉冲激光去除金刚石的机理及过程,建立了物理模型和数学模型,并对传热学模型进行离散处理,通过大型有限元分析软件ANSYS对烧蚀过程进行模拟仿真,得到了金刚石颗粒耦合的仿真温度场及应力场。对求解出的仿真结果进行理论分析,得到了声光调Q YAG激光烧蚀金刚石的理论阈值,计算出各种激光参数条件下单脉冲去除金刚石深度并进行了热应力分析,得到了烧蚀变质层的理论厚度。 采用声光调Q YAG脉冲激光烧蚀金刚石颗粒,用SEM检测了不同烧蚀参数的烧蚀结果,总结出不同激光参数去除金刚石的规律,研究了各个参数对金刚石变质层的影响,证明了应用脉冲激光修整青铜金刚石砂轮的可行性。对比了理论仿真结果与实验结果的差别,阐明了产生差别的原因,验证了理论模型的合理性。 第一次定量分析了金刚石磨粒的变质层厚度,证明了采用合理的激光参数对金刚石颗粒进行烧蚀,可以减小变质层厚度甚至不产生变质层,利用划擦试验研究了修整后金刚石磨粒的磨削能力,证明了修整后的砂轮磨粒仍有较好的磨削能力。更多还原

【Abstract】 Superabrasives (diamond and CBN) wheels have excellent grinding performance, in the field of precise, super precise grinding, difficult processing material has extensive application prospect. Because of exceed the hard abrasive property of Superabrasives wheels, adopt tradition method based on force to repair Superabrasives wheels is nearly impossible to meet the requirement of the development of industry, which affected the appliance of Superabrasives wheels. The laser based on heat action, can repair the Superabrasives wheels easy, which method has aroused countries scholar. This paper maintain the domestic and international research present situation of Superabrasives wheels, pointed out the deficiency of current stage laser repair. Put forward the advantage and the characteristic of repairing Superabrasives wheels by acoustic-optic Q-switched pulse laser .Reasonable parameters of truing and dressing are found through the single laser pulse ablation experiment. An online workpieces position measuring and closed loop control system is developed. Ideal precision of truing has been obtained. Good wheel surface topography has been obtained. Truing and dressing can be carried out at the same time. The effect of dressing and truing has been analysed through the test of grind examination.Used the single pulse laser to ablate the diamond grain , Analysed the mechanism and process, having established physical model and mathematics model, the ablation process was imitated by software ANSYS , the coupling stress and the temperature field was received .As a result, the theoretical threshold value of ablation diamond by acoustic-optic Q-switched pulse laser have gotten, the single pulse exclude diamond depth in various laser parameter conditions have carried out, the thermal stress and the theoretical thickness of carbonization layer was calculated.Used SEM detected the ablation result with different ablation parameter, summarize the exclude rules of different laser parameter and technics parameters, have compared the difference of experiment result and theoretical emulation result. The width of carbonize layers was measured by scrape experiment, proved diamond grain would keep the grinding ability after laser ablation. Through grinding experiment, we compared the size of the grinding force between laser repair measure and traditional machinery measure.更多还原