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介绍了一种新兴的加工技术,超声振动-气体介质电火花复合加工技术.通过分析和实验探讨超声振动-气体介质电火花复合加工中影响表面质量的因素,并提出改进措施. 相似文献
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为了研究超声振动和混粉对电火花加工的影响,基于传热理论,结合超声和混粉特性建立了超声混粉电火花传热模型。基于建立的传热模型对超声混粉电火花加工去除材料过程进行瞬态热力学仿真,并通过实验验证了仿真结果的准确性。通过仿真和实验分析了普通电火花、超声电火花、混粉电火花和超声混粉电火花四种加工方式,结果表明超声混粉电火花加工效率比普通电火花加工效率提高了23%。加入混粉和施加超声可以减少加工表面积碳,提高表面质量;可以使放电凹坑变得更加规则,使表面粗糙度降低。混粉电火花加工相对于普通电火花加工其表面粗糙度平均降低了8.9%,超声混粉电火花表面粗糙度相对于普通电火花平均降低了4.3%。 相似文献
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为解决钛合金在煤油介质中电火花加工效率低及在蒸馏水介质中加工表面质量差的问题,提出利用乳化剂将煤油和蒸馏水超声振动后形成水包油型乳化液作为工作介质的加工方法。分别以煤油、水包油型乳化液和蒸馏水为工作介质,对钛合金TC4进行放电加工试验,从加工效率、电极相对损耗率和表面质量三个方面,对比研究了不同工作介质中钛合金电火花加工的特性。试验结果表明:水包油型乳化液中的加工效率是煤油中加工效率的两倍左右,工件表面粗糙度值Ra比蒸馏水中的Ra值减小了15%~20%,加工后工件表面微裂纹较少,表面较平整,但其电极相对损耗率高。 相似文献
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Anirban Bhattacharya Ajay Batish Naveen Kumar 《Journal of Mechanical Science and Technology》2013,27(1):133-140
The present study reports the results of an experimental work carried out to evaluate the improvement in machined surface properties of die steels machined using powder mixed electric discharge machining (PMEDM) process. Two surface responses, surface finish and microhardness were analyzed for changes when machined with Si, W and graphite powders mixed in dielectric fluid. The machined surfaces were subsequently analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) to study the element migration from powder, dielectric and the tool. The powder mixed with dielectric and its concentration, current and pulse on time were identified as the significant factors affecting surface finish. Brass electrode and tungsten powder resulted in good surface finish. Amongst the dielectrics used, kerosene provided a better cooling effect whereas EDM oil resulted in better surface finish. The microhardness of the machined surface was also affected by powder and its concentration, current, pulse on time and electrode material. W-Cu electrode and W powder resulted in a higher microhardness. The SEM and EDS analysis showed significant migration of material from the suspended powder, electrode and dielectric to the machined surface. 相似文献
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Surface region plastic deformation of Inconel-718 nickel-base superalloy workpieces was evaluated when machined under orthogonal cutting conditions at various cutting speeds. Plastic deformation analysis was accomplished by determining the residual stress and plastic strain distributions in the surface region. The residual stresses were tensile and maximum near the surface and decreased in magnitude with an increase in depth beneath the machined surface. Similarly, the plastic strains were maximum near the surface and decreased with an increase in depth beneath the machined surface. In addition, a finite element simulation of orthogonal machining was carried out for predicting the residual stress and plastic strain distribution. In general, the trend of the curves predicted by the finite element model was similar to those found experimentally. 相似文献
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Disc milling strategy has been applied in grooving for decades for its capacity to provide huge milling force on the difficult-to-cut material. The processing efficiency of machined components thus can be tremendously improved with the application of disc milling. However, the fundamental research of the mechanisms of disc milling on cutting metal materials, especially on titanium alloys, is lacking in the literature. In this study, the milling force and temperature were inspected in disc milling grooving experiment, and the effect of thermal-mechanical coupling on surface integrity of titanium alloy, including surface roughness, surface topography, surface and subsurface residual stress, microstructure, and microhardness, was analyzed. The results showed that a better surface quality can be obtained at the center of the surfaces compared to the marginal regions on the same machined surface. Residual compressive stress was generated on the machined surface and subsurface and gradually reduced to zero with an increase in depth. The microstructure of lattice tensile deformation was emerged along feed direction, while the phase transition was not produced. A hardened layer was found on the machined surface and subsurface, mostly causing by the mechanical loads and oxidation reaction. 相似文献
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Minghai Wang Wei Wang Zesheng Lu 《The International Journal of Advanced Manufacturing Technology》2012,60(5-8):473-485
A new method was proposed for simulating the anisotropic surface quality of machined single-crystal silicon. This represents the first time that not only the mechanical properties of silicon, but also the crystal orientation, which is closely linked to the turning process, have been given consideration. In this paper, the crystallographic relationship between machined crystal planes and slip planes involved in ultra-precision turning was analyzed. The elasticity, plasticity, and brittleness properties of silicon in different crystal orientations were calculated. Based on the brittle–ductile transition mechanism of ultra-precision turning of single-crystal silicon, the orientation dependence of the surface quality of (111), (110), and (100) crystal planes were investigated via computer simulation. According to the simulation results, the surface quality of all machined planes showed an obvious crystallographic orientation dependence while the (111) crystal plane displayed better machinability than the other planes. The anisotropic surface properties of the (111) plane resulted from the continuous change of the cutting direction, which causes a change of actual angle between the slip/cleavage plane and machined plane. Anisotropic surface properties of planes (100) and (110) result from anisotropy of mechanical properties and the continuous changes of the cutting direction, causing the actual angle between slip/cleavage plane and machined plane to change simultaneously. A series of cutting experiments were carried out on the (111) and (100) crystal planes to verify the simulation results. The experimental results showed that cutting force fluctuation features and surface roughness are consistent with the anisotropy characteristics of the machined surface as revealed in simulation studies. 相似文献
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用试验的方法研究了奥-贝球墨铸铁的加工表面形态、已加工表面粗糙度,分析了切削用量和刀具几何角度对加工表面粗糙度的影响.结果表明,已加工表面质量与刀具切削刃不平整及材料组织有关。为提高加工表面质置,必须优选切削参数,重视刀具磨损、后刀面粗糙度及工件材料组织的缺陷。 相似文献
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采用声发射技术对工件材料为A16061-T6的微切削表面轮廓进行了实时测量.采集监控微切削加工表面时产生的声发射均方根信号,并与表面轮廓仪测得的结果进行对比.研究表明,声发射均方根信号与微切削表面形貌很好的相对应,因此,声发射技术适于微切削表面形貌的监测.研究了切削用量(每齿进给量和主轴转速)与表面形貌之间的关系,微切削的每齿进给量对表面粗糙度影响较大. 相似文献
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Fuzeng Wang Jun Zhao Anhai Li Hongxia Zhang 《The International Journal of Advanced Manufacturing Technology》2014,73(1-4):137-146
In the present study, high-speed side milling experiments of H13 tool steel with coated carbide inserts were conducted under different cutting parameters. The microhardness and microstructure changes of the machined surface and subsurface were investigated. A finite element model, taking into account the actual milling process, was established based on the commercial FE package ABAQUS/Explicit. Instantaneous temperature distributions beneath the machined surface were analyzed under different cutting speeds and feed per tooth based on the model. It was found that the microhardness on the machined surface is much higher than that in the subsurface, which indicates that the surface materials experienced severe strain hardening induced by plastic deformation during the milling process. Furthermore, the hardness of machined surface decreases with the increase of cutting speed and feed per tooth due to thermal softening effects. In addition, optical and scanning electron microscope (SEM) was used to characterize the microstructures of cross sections. Elongated grains due to material plastic deformation can be observed in the subsurface, and white and dark layers are not obvious under present milling conditions. The thickness of plastic deformation layer beneath the machined surface increases from 3 to 10 μm with the increase of cutting speed and feed per tooth. The corresponding results were found to be consistent and in good agreement with the depth of heat-affected zone in finite element analysis (FEA). 相似文献
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精密加工表面完整性的研究及其进展 总被引:4,自引:0,他引:4
对国内、外精密切削加工中表面完整性韵研究工作进行了系统的概述和分析,给出精密加工表面完整性的概念, 指出精密切削加工表面完整性领域研究工作的重点及发展的主要方向。针对我国目前的研究现状和水平,提出了系统 开展精密加工表面完整性研究的对策。 相似文献