表面微织构硬质合金刀具干切削性能研究

发布时间：2018-06-03 11:57

本文选题：表面微织构 + 硬质合金刀具　；参考：《湖南科技大学》2017年硕士论文

【摘要】：由于切削液的使用对环境和操作工人产生危害,使得干切削的应用越来越广泛,但干切削导致剧烈地摩擦和粘附,使刀具寿命降低,并影响加工质量。具有一定表面微观结构的非光滑摩擦表面(表面织构)往往具有更小的摩擦力,将表面织构应用于刀具切削过程中,可以实现刀具的减摩抗磨,但其对干切削过程的影响机理仍不清楚。为了提高刀具切削性能,本文从探究表面微织构影响干切削过程的机理出发,综合运用力学、材料学、现代切削理论,结合有限元分析和切削实验,对表面微织构刀具的设计、制备和切削性能等方面开展研究工作。论文主要研究内容如下:(1)对无织构和微织构刀具非自由斜角切削45钢的过程进行有限元分析,对比分析了MT-0、MT-45、MT-90和MT-135刀具的切削力、切削温度和刀具应力,结果表明微织构的存在改变了刀具的切削温度和应力分布;研究了不同宽度、深度和间距的微织构对刀具的切削温度和应力的影响,分析了切削速度、进给量和背吃刀量对微织构刀具切削温度和应力的影响;研究了微织构引起的“二次切削”现象,结果表明较小的微织构宽深比可避免此现象的产生。(2)采用激光加工技术制备出MT-0、MT-45、MT-90和MT-135刀具,将其后处理并对其形貌进行检测。开展了微织构刀具的干切削实验,分析了微织构形态对刀具三向切削力、前刀面平均摩擦系数、前刀面形貌的影响,研究了无织构刀具和MT-135刀具的切削力和前刀面平均摩擦系数随微织构深度和间距、切削速度、进给量和背吃刀量的变化。(3)研究了微织构形态对切屑形貌的影响,对其形成过程及卷曲方式进行分析,探讨了微织构刀具的切屑形成机理,揭示了表面微织构影响干切削过程的机理。在切削过程中,微织构减小了刀-屑实际接触长度,有利于降低切削力和切削温度;微织构可以存储刀-屑摩擦界面的碎屑,减小犁沟效应,从而减小摩擦和刀具磨损。
[Abstract]:Because the use of cutting fluid is harmful to environment and operation workers, dry cutting is more and more widely used, but dry cutting leads to severe friction and adhesion, reduces tool life and affects machining quality. The non-smooth friction surface (surface texture) with certain surface microstructure often has smaller friction force. Applying surface texture to cutting process of cutting tool can realize anti-friction and anti-wear of cutting tool. However, the mechanism of its influence on the dry cutting process is still unclear. In order to improve the cutting performance of the cutting tool, this paper discusses the mechanism of the influence of surface microtexture on the dry cutting process, and synthetically applies mechanics, material science, modern cutting theory, combined with finite element analysis and cutting experiment, to design the surface microtexture tool. Research work on preparation and cutting performance has been carried out. The main contents of this paper are as follows: (1) finite element analysis is carried out on the process of cutting 45 steel with non-free oblique angle of non-texture and micro-texture cutting tools, and the cutting force, cutting temperature and tool stress of MT-0O MT-45MT-90 and MT-135 tools are compared and analyzed. The results show that the existence of microtexture changes the cutting temperature and stress distribution of the tool, the influence of different width, depth and spacing on the cutting temperature and stress is studied, and the cutting speed is analyzed. The effects of feed rate and back feed on the cutting temperature and stress of microtexture cutter are studied, and the phenomenon of "secondary cutting" caused by microtexture is studied. The results show that the smaller aspect ratio of microtexture can avoid this phenomenon. (2) MT-0 MT-45 MT-90 and MT-135 cutters are fabricated by laser processing, and the morphology of MT-0 MT-45 MT-90 and MT-90 is examined. The dry cutting experiments of microtexture cutting tools were carried out, and the effects of microtexture shape on the cutting force, the average friction coefficient of the front cutting face and the morphology of the front tool face were analyzed. The effects of the cutting force and the average friction coefficient of the front cutting face on the microtexture depth and spacing, cutting speed, feed rate and the back feed rate of the cutting tool were studied. The influence of the microtexture morphology on the chip morphology was studied. The forming process and crimp mode of microtexture cutting tools were analyzed, and the mechanism of chip formation of microtexture cutting tools was discussed, and the mechanism of surface microtexture affecting dry cutting process was revealed. In the process of cutting, the microtexture reduces the actual contact length of the cutter and chip, which is helpful to reduce the cutting force and cutting temperature, and the microtexture can store the chips at the friction interface of the knife and chip, and reduce the ploughing effect, thus reducing the friction and tool wear.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG501

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