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高速磨削,徐进磨削,镜面磨削以及适应控制磨削等新技术新工艺的不断出现、推广和提高,促使我们必须对磨削过程的本质及其所表现出来的现象作进一步深入的研究。在磨削过程中,砂轮与工件之间的力学作用引起的双方发生的物理变化和化学变化产生了磨削力和磨削热,从而使磨屑不断形成,在工件上获得了一定的尺寸和形状精度,表面光洁度和机械物理性能。同时磨粒亦趋于磨钝或脱落,最终可能在磨削工艺系统中发生振动而使工件和砂轮表面均受到了破坏。由于磨削条件的改变,磨削过程也因此而会发生变化。不同的砂轮(磨料,粒度,硬度,组织,结合剂),不同的修正工具及工艺参数,不同的工件材料及机械性能,以及它们之间的相对运动的关系(砂轮线速度,进给率,工件线速度等)均会在磨削过程中影响磨屑的形成过程及其结果。因此在磨削过程中,砂轮进入工件表面层的相对摩擦的程度,耕犁角度、深度、长度,工件表面层弹性和塑性变形的程度,切除下来的磨屑的几何形状就都受上述许多因素的影响。伴随着磨屑形成消耗的一定功率产生了大量磨削热,其中大部分进入到工件中,使工件表面温度升高,并有可能改变表面层的金相组织,甚至会引起残余应力和裂纹。与切除磨屑的同时砂轮上的砂粒因机械磨损和化学磨损会逐步钝化,砂轮表面可能受到磨屑的堵塞而逐渐丧失切削能力,也有可能发生自励作用而延长磨削时间。冷却润滑液的使用会影响到工件和砂轮表面的物理变化和化学变化。在磨削过程中存在于砂轮与工件之间的磨削力还会引起工艺系统的变形,其变化可能促使工艺系统自激振动的发展,影响到加工质量,生产率和工具寿命。研究磨削机理也就是应用物理学和化学原理等来研究磨削过程中统一体(工艺系统)中的对立双方(砂轮系统与工件系统)的组成功能,相互的作用,发展变化及其結果,研究各因素的影响,相互关系,分清主次,从而掌握其内在规律。这对于发展磨料磨具的新品种,不断提高磨削加工工艺水平,研制新的冷却润滑液,改进磨床结构发展新的磨床品种,尤其是对于发展、提高和创造新的磨削工艺(高效、高精度磨削,适应控制磨削等)有着重大的作用。近年来,我国对磨削机理也着手进行了研究,为了赶超世界先进水平,必须了解国外关于磨削机理的研究动态。这里刊登了一篇由华中工学院机制教研组根据国外期刊资料所汇总编写的文章,供读者参考。
High-speed grinding, Xu Jin grinding, mirror grinding and grinding and other adaptive control of new technology and new technology continue to appear, promote and improve, prompting us to the grinding process must be the essence and the phenomenon of its further the study. In the process of grinding, the physical and chemical changes caused by the mechanical action between the grinding wheel and the workpiece have resulted in the grinding force and the grinding heat, so as to make the grinding debris continuously form and get a certain size on the workpiece Shape accuracy, surface finish and mechanical and physical properties. At the same time abrasive particles tend to blunt or fall off, the final grinding process may occur in the system vibration and the workpiece and the wheel surface have been destroyed. Due to changes in grinding conditions, grinding process will therefore change. The relationship between different grinding wheels (abrasive, grain size, hardness, texture, bonding agent), different correction tools and process parameters, different workpiece materials and mechanical properties, and the relative movement between them (wheel speed, feedrate, Workpiece line speed, etc.) will affect the formation of wear debris in the grinding process and its results. Therefore, during the grinding process, the relative friction of the grinding wheel into the surface layer of the workpiece, the angle, depth and length of the plow, the degree of elastic and plastic deformation of the surface layer of the workpiece, the geometry of the cut debris are all affected by many factors Impact. A large amount of grinding heat is generated with a certain amount of power consumed in the formation of wear debris, most of which enters the work piece, increasing the surface temperature of the work piece and possibly changing the microstructure of the surface layer and even causing residual stresses and cracks. And the removal of debris at the same time on the grinding wheel grit due to mechanical wear and chemical wear and tear will be gradually passivation, grinding wheel surface debris may be blocked gradually loss of cutting capacity, but also may occur self-excitation to extend the grinding time. The use of cooling lubricants affects the physical and chemical changes of the workpiece and wheel surfaces. The grinding forces that exist between the grinding wheel and the workpiece during the grinding process can also cause the deformation of the process system, which may lead to the development of self-excited vibration of the process system, affecting the processing quality, productivity and tool life. Studying the grinding mechanism is to study the compositional functions, mutual actions, development changes and the results of the two parties (grinding wheel system and workpiece system) in the unification (process system) during the grinding process by using the principles of physics and chemistry, Study the influence of various factors, the relationship between each other, distinguish primary and secondary, so as to grasp its inherent law. This is the development of new varieties of abrasives, and constantly improve the level of grinding process, the development of new cooling lubricant, grinding machine structure to improve the development of new grinder varieties, especially for the development, improvement and creation of new grinding process (efficient, High-precision grinding, grinding and other adapt to control) has a significant role. In recent years, China also started to study the grinding mechanism, in order to catch up with the advanced world level, we must understand the foreign research on the grinding mechanism. Here published an article by the mechanism research group of Huazhong Institute of Technology compiled according to the summary of foreign periodicals for readers reference.