共查询到18条相似文献,搜索用时 890 毫秒
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通过运用有限元分析软件ABAQUS建立二维平面单颗磨粒切削模型,对Si C颗粒体积分数为45%的Si Cp/Al的加工过程进行了仿真与实验研究,分析了不同的加工参数对切削力产生的影响,并研究了切削后已加工表面的表面形貌。实验结果和仿真结果均表明在一定条件下切削深度比切削速度对切削力的影响更显著,当切削深度一定时,切削速度对切削力的变化影响不大;当切削速度一定时,切削深度越大,切削力越大。单颗金刚石磨粒对复合材料中增强相的作用主要表现在Si C颗粒的旋转、移动,而由此造成的不连续的坑洞是加工过程中表面形成的主要缺陷。 相似文献
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《机械制造与自动化》2016,(2):57-60
磨削过程是由砂轮表面成千上万个形状各异的磨粒共同参与的切削过程。考虑到材料的本构关系、切屑与工件的分离准则及切屑与磨粒间的接触和摩擦,利用非线性显式动力学分析软件LS-DYNA对单颗磨粒切削过程进行了数值仿真模拟,得到了工件内部应力的变化规律。结果表明:成屑过程是材料受到切削刃挤压产生剪切滑移的过程;在切削初始,切削力急剧增大,当切削达到稳定状态时,材料的最大等效应力在某一值附近波动;当切削速度增大时,材料的最大等效应力将增大。运用此方法可以直观地观察切削过程的变化,进而可对磨削工艺参数进行优化。 相似文献
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切削速度影响切削力的有限元模拟 总被引:1,自引:0,他引:1
运用有限元数值模拟技术对三维金属切削过程进行仿真。分析了切削速度对切削力的影响,并对仿真数据进行拟合处理,导出了不同方向上切削力与切削速度的关系式。探讨了刀具和工件不同阶段应力变化特征。模拟结果表明,刀尖处等效应力最大,切削力在低速切削时,随切削速度的增加而增大,当到达某临界速度时,将随着切削速度的增加而减小。 相似文献
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《制造技术与机床》2017,(5)
为了研究CBN磨粒砂轮在轴向超声振动条件下的磨削特性,通过轴向超声振动辅助条件下单颗CBN磨粒切削试件的试验,以磨削力为研究对象,研究了轴向超声振动辅助条件下单颗CBN磨粒切削力,从微观角度进行磨粒的运动分析。研究表明:轴向超声辅助条件下的切削力,无论是单颗磨粒所受的法向力F_n还是切向力F_t的值均小于普通条件下的切削力。轴向超声振动辅助条件下单颗CBN磨粒切削运动轨迹是由刀具围绕工件的旋转运动和刀具的高频振动复合而成,其轨迹整体符合正弦曲线轨迹。通过正交试验得出,在一定条件下,轴向超声辅助下的切削力随磨粒切削速度、磨削深度的增大而增大,普通加工中随磨粒大小的增大而增大,超声加工时随磨粒增大有先增后减的趋势。此次试验研究对后期整个CBN砂轮在超声辅助条件下磨削的研究以及CBN砂轮的制备方面都有一定的意义和价值。 相似文献
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通过建立单颗磨粒磨削模型,采用ABAQUS软件对GH4169高温合金的磨削过程进行有限元仿真,探究单颗磨粒在不同参数下对GH4169高温合金工件磨削过程的影响。研究表明:磨粒从切入工件后到切出工件前,磨削力稳定波动,且与磨粒前角和磨削深度显著相关,切向磨削力随着磨粒前角增大而显著减小,随着磨削深度的增大而显著增大;最高磨削温度出现在磨粒切入工件的时刻,且与磨粒前角、磨削深度和磨削速度相关;磨粒前角对磨屑的形状影响显著,磨粒前角越大,磨屑越难排出,磨削速度对磨屑的形状影响较小,磨削深度影响磨屑的厚度和长度。 相似文献
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Angelos P. MARKOPOULOS Ioannis K. SAVVOPOULOS Nikolaos E. KARKALOS Dimitrios E. MANOLAKOS 《Frontiers of Mechanical Engineering》2015,10(2):168
In this paper the nano-metric simulation of grinding of copper with diamond abrasive grains, using the molecular dynamics (MD) method, is considered. An MD model of nano-scale grinding, where a single diamond abrasive grain performs cutting of a copper workpiece, is presented. The Morse potential function is used to simulate the interactions between the atoms involved in the procedure. In the proposed model, the abrasive grain follows a curved path with decreasing depth of cut within the workpiece to simulate the actual material removal process. Three different initial depths of cut, namely 4 ?, 8 ? and 12 ?, are tested, and the influence of the depth of cut on chip formation, cutting forces and workpiece temperatures are thoroughly investigated. The simulation results indicate that with the increase of the initial depth of cut, average cutting forces also increase and therefore the temperatures on the machined surface and within the workpiece increase as well. Furthermore, the effects of the different values of the simulation variables on the chip formation mechanism are studied and discussed. With the appropriate modifications, the proposed model can be used for the simulation of various nano-machining processes and operations, in which continuum mechanics cannot be applied or experimental techniques are subjected to limitations. 相似文献
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Wafer rotational grinding is widely employed for back-thinning and flattening of semiconducting wafers during the manufacturing process of integrated circuits. Grit cutting depth is a comprehensive indicator that characterizes overall grinding conditions, such as the wheel structure, geometry, abrasive grit size, and grinding parameters. Furthermore, grit cutting depth directly affects wafer surface/subsurface quality, grinding force, and wheel performance. The existing grit cutting depth models for wafer rotational grinding cannot provide reasonable results due to the complex grinding process under extremely small grit cutting depth. In this paper, a new grit cutting depth model for wafer rotational grinding is proposed which considers machining parameters, wheel grit shape, wheel surface topography, effective grit number, and elastic deformation of the wheel grit and the workpiece during the grinding process. In addition, based on grit cutting depth and ground surface roughness relationship, a series of grinding experiments under various grit cutting depths are conducted to produce silicon wafers with various surface roughness values and compare the predictive accuracy of the proposed model and the existing models. The results indicate that predictions obtained by the proposed model are in better agreement with the experimental results, while accuracy is improved by 40%–60% compared to the previous models. 相似文献
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《Tribology - Materials, Surfaces & Interfaces》2013,7(4):235-240
AbstractGrinding processes require a high energy input per unit volume of material removed, which is converted to heat at the grinding zone, resulting in increased force and wear. In the present study, the influence of grinding parameters like work speed and depth of cut on grinding forces and energy was studied. An attempt has been made to study the forces and energy involved while grinding aluminium alloy (A356)/silicon carbide (SiC) composite material with different grinding wheels. Experiments were carried out on a surface grinding machine. Three different types of wheels like SiC, cubic boron nitride (CBN) and diamond wheels were used. The grinding forces increased with increase in depth of cut and work speed. SiC exhibited high grinding force compared to the CBN wheel. In the case of the diamond wheel, it was even less. The specific grinding energy was highest for the diamond wheel followed by CBN and SiC wheels. The specific grinding energy decreased with increase in depth of cut and work speed. 相似文献
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从比切削能和比摩擦能的大小变化与磨削参数的关系出发,研究了磨削加工中的尺寸效应问题,结果认为:比切削能的尺寸效应是金属剪切流动应力的尺寸效应和磨粒顶端钝圆影响的综合作用结果;当磨削深度或工件进给速度减小时,平均未变形切屑厚度减小,金属材料的剪应变效应和剪应变率效应增强,而热软化效应减弱,从而金属材料的剪切流动应力增大;当未变形切屑厚度减小时,磨粒顶端钝圆的影响增大;比摩擦能的尺寸效应是由于工件和砂轮的实际接触面积与磨削深度之间存在非线性关系及工件和砂轮间的摩擦因数的速度效应造成的;当工件进给速度减小时,工件与砂轮磨损平面间的摩擦因数增大。 相似文献
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This study of the mechanics of grinding used a single grit approach and involved the development of a high frequency dynamometer to measure grinding forces at speeds of up to 37 m s?1. Experiments have been carried out using idealised cutters to simulate abrasive grits; the grinding forces, the grinding coefficient and the specific energy were measured for a wide range of cutting speeds and workpiece hardness. For a grit of a given geometry the main factors affecting efficiency were found to be the hardness of the workpiece and the cutting speed.A theoretical model of the grinding process has been developed which enables normal grinding forces to be predicted from the flow pressure of the workpiece and the geometry and cutting efficiency of the grit.The implications of the work are discussed with particular reference to surface finish. 相似文献
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