带减摩槽刀片在加工不锈钢中的应用

通过分析不锈钢切削加工过程中切屑与刀具前刀面之间的摩擦情况,提出减少切屑与刀具前刀面的接触面积能降低切屑与刀具之间的摩擦阻力,从而减小主切削力。据此,设计了两种带减摩槽的三维槽型刀片,并通过切削试验、切削力检测验证了减摩槽能有效减小主切削力并改善刀片槽型断屑性能的结论。     

减摩槽刀片切削过程的Deform仿真

在刀片上设计减摩槽,理论上可以减小刀屑接触面积,进而减小切削力。目前,对减摩槽刀片的研究仍停留在切削实验阶段。本文用Deform 3D软件对有无减摩槽的两种刀片进行了模拟仿真,分析了减摩槽对切削力大小、切削温度、切屑的有效应力及刀具塑性变形的影响。仿真结果对刀具减摩槽的设计及选用具有参考价值。     

整硬麻花钻容屑槽与法向前角对钛合金钻削性能的影响

采用UG NX11.0软件建立了三种不同卷屑角的容屑槽,以锥面刃磨的方式构建钻尖三维模型。测量主切削刃的法向前角并绘制法向前角的分布曲线,分析三种曲线之间的关系。利用AdvantEdge有限元仿真软件模拟钻削过程中的切削力、切削形貌、切削温度和应力分布,并通过切削试验验证了有限元模拟的可靠性。结果表明：容屑槽卷曲角直接影响主切削刃法向刀具前角的分布,且主切削刃的法向刀具前角越大,切削越锋利,切削力越小;在一定范围内,随着容屑槽卷曲角α增大,轴向切削力减小,且切屑卷曲直径也越小,有利于排屑和提高刀具寿命。     

断屑槽槽型在控屑过程中对刀具振动的影响

通过ABAQUS有限元软件分别对梯形、直线圆弧型和梯形双槽结构断屑槽刀具切削Ti6Al4V钛合金材料进行三维切削仿真,并分析其切削力的波动,得到断屑槽槽型在控制切屑卷曲过程中对刀具在主运动方向、进给方向和切削深度方向振动的影响。经过仿真发现,梯形、直线圆弧型和梯形双槽结构断屑槽在控制切屑卷曲的过程中对刀具振动的影响各不相同。三种槽型结构中,梯形断屑槽刀具的振动最弱,直线圆弧型断屑槽刀具的振动最强。     

硬质合金刀片断屑槽槽型对其切削性能的影响

采用具有多种断屑槽槽型的同种基体材质的刀片进行车削实验,应用高速摄影机捕捉切削区域切屑产生、流出、卷曲和折断过程。通过磨损测量仪观测断屑槽,并结合切屑形态分析,明确断屑槽合理几何形状;通过三维受力分析仪采集切削过程中的振动和切削力信号,揭示断屑槽对切削力的影响规律;综合切削参数、断屑槽几何结构和切削力三方面的因素,最终确立断屑槽槽型与进给量对切屑折断的作用机制。研究数据以期为断屑槽设计与车削刀具的应用提供数据支撑。     

微织构衍生切削下的钛合金正交微切削性能分析

针对微织构刀具加工过程中的衍生切削效应,利用正交微切削单元开展了微坑刀具及无织构刀具的钛合金微切削实验,从切屑底面形貌、微坑黏结状态等方面分析了微坑刀具微切削性能;通过ABAQUS软件对微织构刀具微切削钛合金过程进行有限元模拟,分析微坑织构的衍生切削作用对刀-屑接触应力分布及切削力的影响,优化设计微坑边缘过渡区参数并进行切削仿真分析。实验和仿真结果表明,微坑会减小前刀面黏结,存储微屑,减小刀-屑接触应力,提高刀具减摩性能;但微坑与切屑的衍生切削作用会增大瞬时切削力,降低切削过程平稳性。此外,微坑过渡区优化可改善切削过程波动,降低切削力,改变切屑形态,改善切屑在微坑的流入/流出状态,有助于减小微坑织构衍生切削效应,提高织构的减摩效果。     

拉刀多开分屑槽的又一作用

拉刀进行拉削作业时,经过工件的每个切削刃都进行切削,而且圆周上每个切削刃的吃刀量是相同的,并形成卷屑,圆拉刀属于封闭式切削刀具,切屑成环状且套在拉刀容屑槽内,清除极为困难,对生产十分不利。所以,在刀齿上必须开分屑槽。分屑槽的作用就是减小切屑宽度,将切屑分成小段,从而减少与拉刀的粘着力,避免粘刀。     

带减摩槽刀片切削机理的研究

对带减摩槽刀片的切削机理进行了理论研究,考察了减摩槽对主切削力（ＦＺ）以及切削变形和断屑性能的影响,在此基础上得出三维断屑槽设计的一些有益结论,并通过平前刀面刀片和带减摩槽刀片的对比切削试验验证了这些结论,最后据此设计了一种新型断屑槽。     

聚晶金刚石刀具的断屑槽尺寸参数设计

为解决聚晶金刚石(PCD)刀具在铝合金材料切削过程中的切屑缠绕问题,在PCD刀具的前刀面上设计了断屑槽.通过对切屑受力过程和断屑槽断屑机理的分析、切削几何关系的推导和有限元切削仿真实验,提取了5个PCD刀具断屑槽参数,即棱带宽度、倾角、反屑角、槽宽和反屑面转角.建立了PCD刀具断屑槽棱带宽度和反屑角的计算公式;改进了槽...     

断屑槽槽背几何形状对车削钛合金的影响研究

为研究断屑槽槽背的几何形状对车削加工的影响,选用硬质合金和钛合金为研究对象,基于ABAQUS有限元软件建立三维切削仿真模型,通过单因素实验法研究了三种不同断屑槽槽背对切削力、切削热和切屑卷曲程度等的影响.结果表明:在实验参数的范围内,柱面型槽背刀具较单斜面型、斜面和柱面组合型槽背刀具的切削性能更好;柱面型槽背刀具切削所...     

Performance of the self-lubricating textured tools in dry cutting of Ti-6Al-4V

Surface textures were made using laser on the rake or flank face of the cemented carbide (WC/Co) inserts. Molybdenum disulfide solid lubricants were filled into the textured grooves to form self-lubricating textured tools. Dry cutting tests on Ti-6Al-4V were carried out with these self-lubricating textured tools and conventional tool. The machining performance was assessed in terms of the cutting forces, cutting temperature, chip thickness ratio, friction coefficient at the tool–chip interface, and tool wear. Results show that the cutting forces and cutting temperature of the self-lubricating textured tools were reduced compared with that of the conventional tool. The application of the self-lubricating textured tool with elliptical grooves on its rake face can reduce the tool–chip friction coefficient and the chip thickness ratio. The tool life of the textured tools is improved compared with that of the conventional tool. The effectiveness of the self-lubricating textured tools in improving cutting performance is related to the cutting parameter.     

微织构(W,Mo)C基刀具和YG8刀具对钛合金干切削性能的影响

刀具切削钛合金时存在切削温度高、单位面积上切削力大等问题,微织构刀具可以有效减小摩擦力,减小切削力。通过正交实验法设计微织构参数,研究微织构参数对Al 2O 3/La 2O 3/(W,Mo)C无黏结相硬质合金刀具以及YG8刀具切削钛合金实验的切削性能影响。实验结果表明,合适参数的沟槽型微织构能有效降低Al 2O 3/La 2O 3/(W,Mo)C无黏结相硬质合金刀具和YG8刀具切削TC4钛合金的切削力,相同沟槽参数下,无黏结相硬质合金刀具的切削力明显低于YG8刀具的切削力;合适参数的沟槽型微织构能有效降低刀具刀屑界面的摩擦系数,相同沟槽参数下,无黏结相硬质合金刀具的摩擦系数大都低于YG8刀具的摩擦系数;沟槽深度10μm、沟槽间距100μm以及沟槽宽度30μm的沟槽参数下,切削钛合金时,无黏结相硬质合金刀具前刀面无明显磨损,后刀面只有边界磨损,YG8刀具发生崩刃,前刀面出现切屑的滞留。     

前刀面槽型结构对D型刀片车削球墨铸铁性能的影响

通过切削力、磨损和冲击切削试验,研究了前刀面槽型结构对D型刀片车削球墨铸铁切削性能的影响。试验结果显示,刀具的第一前角对切削力的影响最大;在10°~15°范围内,刀具前角越大,切削力越低;棱带宽度大的刀片具有更加优异的耐磨损性能;具有正刃倾角的刀片显示出更优异的耐冲击性能。     

A numeric investigation of friction behaviors along tool/chip interface in nanometric machining of a single crystal copper structure

The interaction between the tool rake face and the chip is critical to chip morphology, cutting forces, surface quality, and other phenomena in machining. A large body of existing literature on nanometric machining or nano-scratching only considers the overall friction behavior by simply regarding the total force along tool movement direction as the friction force, which is not suitable for describing the intriguing friction phenomena along the tool/chip interface. In this study, the molecular dynamic (MD) simulation is used to model the nanometric machining process of single crystal copper with diamond tools. The effects of three factors, namely, tool rake angle, depth of cut, and tool travel distance, are considered. The simulation results reveal that the normal force and friction force distributions along tool/chip interface for all cases investigated are similarly shaped. It is found that the normal force consistently increases along the entire tool/chip interface when a more negative rake angle tool is used. However, the friction force increases as the rake angle becomes more negative only in the contact area close to the tool tip, and it reverses the trend in the middle of tool/chip interface. Meanwhile, the increase of depth of cut overall increases the normal force along the tool/chip interface, but the friction force does not necessarily increase. Also, the progress of tool into the work material does not change the patterns of normal force, friction force, or friction coefficient distributions to a great extent. More importantly, it is discovered that the traditional sliding model with a constant friction coefficient can be used to approximate the later section of friction distributions. However, no friction model for traditional machining is appropriate to describe the first section of friction distributions obtained from the MD simulation.     

Preparation of tungsten disulfide (WS2) soft-coated nano-textured self-lubricating tool and its cutting performance

This paper proposes a new effective dry cutting tool named tungsten disulfide (WS₂) soft-coated nano-textured self-lubricating tool which is fabricated by two steps. First, nano-texture is made on the tool–chip interface of rake face of uncoated YS8 (WC + TiC + Co) cemented carbide cutting inserts by femtosecond laser micromachining technology. Second, WS₂ soft coating is deposited on the nano-textured tool by medium-frequency magnetron sputtering, multi-arc ion plating and ion beam assisted deposition technique. Dry turning tests on 45# quenched and tempered steel were carried out with three kinds of cutting tools: conventional YS8 tool, nano-textured tool (CFT), and WS₂ soft-coated nano-textured self-lubricating tool (CFTWS). Results show that the cutting forces, cutting temperature, the friction coefficient at the tool–chip interface, and the antiadhesive effect of the nano-textured tools were significantly reduced compared with those of the conventional one. The CFTWS tool had the best cutting performance among all the tools tested under the same test conditions. Through cutting force and cutting temperature theoretical analysis and experimental results, four mechanisms responsible were found. The first one is explained as the formation of the WS₂ lubricating film with low shear strength at the tool–chip interface, which was released from the surface nano textures and smeared on the rake face, and served as lubricating additive during dry cutting processes to reduce the cutting forces and cutting temperature. The second one is explained by the reduced contact length at the tool–chip interface of the nano-textured tools; the smaller direct contact area between the chip and tool rake face leads to less friction force, which can also contribute to the decrease of cutting forces and cutting temperature. The third one can be explained that because of the excellent lubricity of the WS₂ lubricating film, the antiadhesive effect can be significantly improved which can reduce adhesive wear of the cutting tool and prolong the tool life. The fourth one can be explained that the advantage of CFTWS tool in cutting forces and cutting temperature is obvious in relatively high-speed and high-temperature conditions may be because of ultra-low friction coefficient, high temperature resistance, and the high oxidation resistance of WS₂ soft coating which is not sensitive to high cutting temperature and high cutting speed can significantly improve the severe dry cutting environment.     

在刀-屑界面持续润滑刀具切削45钢的性能及润滑机理

为提高刀具润滑性能,尽量减少切削液的使用,制备出在刀屑界面持续润滑的新型刀具,能够将切削液通过微通道直接输送到刀屑接触界面内部。采用该新型刀具与普通刀具在干切削和浇注切削液条件下分别进行切削45钢试验,测量了切削三向力,对刀具前刀面磨损面进行SEM微观形貌分析及元素检测,分析了刀具的摩擦磨损特性及润滑机理。试验结果表明,与普通刀具在干切削和浇注切削液条件下相比,刀屑界面持续润滑刀具能够有效减少切削过程中的摩擦磨损,而切削液用量只有传统浇注式切削的1/120。分析前刀面的元素可知,切削液能够更加深入到离主切削刃更近的区域,并能持续供给,这是该刀具具有更好的减摩抗磨效果的主要原因。尽管新型刀具的黏结情况大大缓解,但刀具的磨损机理仍然以黏结磨损和氧化磨损为主。