Ti6A14V钛合金高速切削试验与有限元建模

综合考虑刀具圆角影响的Merchant模型和高速正交切削Ti6AI 4V实验测量的切削力和切屑几何参数,解析求得了"切屑-刀具-工件"摩擦系数。计算表明"刀具-工件"摩擦系数约为"刀具-切屑"摩擦系数的3～7倍,该研究克服了现有文献中对"切屑-刀具-工件"摩擦系数取值的盲目性。基于该摩擦关系,建立钛合金高速切削有限元模型(FEM)。仿真切削力与试验值相比误差小于4.9%:锯齿间距、锯齿高度,及其剪切角与试验值误差均小于5.2%,钛合金高速切削有限元模型得到了有效性验证。     

高速切削技术及高速切削可转位铣刀的研究

高速切削是先进制造技术中最重要的加工工艺之一，而切削刀具是实现这一工艺的关键。论文介绍了高速切削技术，以及高速切削技术要求的高速切削刀具，特别说明的是高速切削铣刀；论述了高速切削的可转位铣刀的特点、切削刀具材料和刀体结构。     

刀具在航空壳体高速切削中的影响研究

高速切削作为一种高效切削的加工方法在航空领域中已广泛应用。影响高速切削的因素非常多,其中刀具对于高速切削有着重要的影响,刀具自身的结构、材料和几何参数,刀具的夹持系统以及加工工艺等直接影响高速切削的效率。通过对刀具自身相关参数及与刀具相关的因素进行分析,结合航空壳体零件在实际加工中的应用实例,进一步掌握刀具在高速切削中的影响,从而提升高速切削在实际应用中的效果,降低企业的加工成本。     

高速切削刀具的研究

高速切削已经成为先进制造工艺的关键技术，集中了机床、工具、控制系统等相关技术多年的研究成果。本文从高速切削的机理出发，分析高速切削对刀具材料、刀具几何结构及刀具装夹防护系统的要求，研究高速切削刀具的设计特点。     

高速切削切具的研究

本文从高速切削的机理出发，分析高速切削对刀具材料，刀具几何结构及刀具装夹防护系统的要求，研究高速切削刀具的设计特点。     

高速切削刀具材料的发展应用研究

发展高速切削是现代切削加工技术的重要趋势,高速切削刀具材料也是影响制造业发展的重要因素.介绍了高速切削刀具材料的特点,具体分析了高速切削加工常见刀具材料硬质合金、陶瓷、金刚石类材料的特性、发展及其应用,并对未来高速切削刀具材料的发展趋势进行了展望.细晶和表面涂层硬质合金材料、氧化铝各系列陶瓷材料以及立方氮化硼(CBN)金刚石类材料是未来高速切削刀具材料发展的方向.根据高速切削刀具材料的特点,应用场合及其发展状态,对其未来的发展提出一些建议.     

高速切削刀具技术

作为先进制造技术,高速切削技术能大幅度地提高加工品质和加工效率,并能降低加工成本.高速切削技术是机械制造业发展的必然趋势.而高速切削刀具技术则是实现高速切削的关键技术之一,笔者主要从刀具材料、刀具结构和刀具动平衡方面来阐述和分析该技术.     

高速切削刀具的发展现状

对国内外高速切削刀具的发展现状进行了综合评述 ,重点介绍了高速切削刀具材料和高速切削刀具技术 (包括刀具动平衡技术、刀柄系统、刀具安全性、可转位面铣刀结构、刀具监测技术等 )的开发及应用     

高速切削中的刀具材料

结合高速切削加工技术和刀具材料的研究,综合论述高速切削加工刀具材料的性能特点、研究进展和应用,展望高速切削加工刀具材料的未来。     

高速切削加工刀具材料

论述了高速切削的概念和优越性,介绍了高速切削加工所使用的先进刀具材料和刀具如：陶瓷刀具、金刚石刀具、立方氮化硼刀具、涂层刀具的性能特点及其应用,探讨了高速切削刀具材料的发展前景和研究方向。     

基于AdvantEdge的斜角车削仿真实验确定刀屑摩擦因数的方法

当使用AdvantEdge软件进行切削仿真实验时，刀屑摩擦因数对仿真结果的影响明显，但现有有限元软件未提供刀屑摩擦因数数据库。为建立一种基于AdvantEdge的斜角车削仿真实验的刀屑摩擦因数确定方法，首先提出基于斜角车削的摩擦力计算方法，然后建立AdvantEdge三维斜角车削仿真模型，设定不同切削速度、切削深度、进给量及摩擦因数，通过AdvantEdge 仿真正交试验，获得刀屑摩擦因数的经验计算公式。为验证刀屑摩擦因数经验计算公式的正确性，设定不同切削速度和切削深度及进给量的斜角车削正交试验，获得切削力数据，并基于摩擦因数经验计算公式求得对应刀屑摩擦因数。利用求得的摩擦因数数据修改AdvantEdge中刀屑摩擦因数参数，进行残余应力切削仿真实验。仿真实验获得的残余应力与实际切削实验获得的残余应力相比，误差在10%以内，证明提出的刀屑摩擦因数确定方法是正确的。     

Experimental assessment of textured tools with nano-lubricants in orthogonal cutting of titanium alloy

In this study, we investigated the effects of composite nano-Cu/WS₂ lubricating oil and single-point diamond indentation-textures on improving the cutting performance of YG8 cemented carbide tools, which is crucial for textures tool applications. The aims of the study were to improve wear resistance and reduce chip adhesion at the tool’s rake face in cutting of titanium alloys. Dot textures with different spacings were fabricated on the surface of YG8 cemented carbide tools through the single-point diamond indentation method, and composite nano-Cu/WS₂ lubricating oil was prepared. Orthogonal cutting tests were carried out under dry cutting and minimal quantity lubricated (MQL) conditions. Investigate the effect of different texture spacing on the cutting performance in the light of cutting forces, friction coefficient, the deformed chip thickness, tool adhesions, and chip morphology. The results show that the dot texture effectively improved the lubrication conditions in machining titanium alloys under the MQL conditions. The dot texture is effective at low speed in the dry cutting conditions. With the increase of cutting speed, the friction coefficient of dot texture tool is affected by texture spacing, and the friction coefficient of DT-200 tool is the smallest. In addition, composite nano Cu/WS₂ lubricating oil forms a lubricating film on the wear path by atomizing the lubricating oil and stores it in the dot texture, which enhances the anti-wear performance in the cutting process and reduces the cutting force and friction coefficient at the tool chip interface. By evaluating cutting force, friction coefficient, chip and tool morphology, it is concluded that DT-100 tool is more effective in improving lubrication conditions.

     

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。     

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.     

Statistical analysis of process parameters in drilling of AL/SICP metal matrix composite

Four micro-holes were made using micro-EDM on rake face of the cemented carbide (WC/TiC/Co) tools. MoS₂, CaF₂, and graphite solid lubricants were respectively embedded into the four micro-holes to form self-lubricated tools (SLT-1, SLT-2, and SLT-3). Dry machining tests on hardened steel were carried out with these self-lubricated tools and conventional tools (SLT-4). The cutting forces, average friction coefficient between tool and chip, and tool wear were measured and compared. It was shown that the cutting forces and tool wear of self-lubricated tools were clearly reduced compared with those of the SLT-4 conventional tool. The SLT-1 self-lubricated tool embedded with MoS₂ just exhibited lower friction coefficient between tool and chip in cutting speed of less than 100?m/min; the SLT-2 self-lubricated tool embedded with CaF₂ possessed lower friction coefficient in cutting speed of more than 100?m/min; and the SLT-3 self-lubricated tool embedded with graphite accomplished good lubricating behaviors steadily under the test conditions. It is indicated that cemented carbide inserts with four micro-holes on rake face embedded with appropriate solid lubricants on rake face is an effective way to reduce cutting forces and rake wear.     

切削工艺参数对切屑形状的影响及其有限元分析

以刚塑性有限元理论为基础,采用有限元仿真技术,对金属正交切削过程中切屑成形进行了模拟仿真,得到了不同的刀具前角和摩擦条件对切屑形状的影响规律。对二维切削过程进行加工实验,结果表明切削模拟结果与实际加工情况比较吻合,可以为实际加工提供参数选择的依据。     

Numerical and analytical modeling of orthogonal cutting: The link between local variables and global contact characteristics

The response of the tool-chip interface is characterized in the orthogonal cutting process by numerical and analytical means and compared to experimental results. We study the link between local parameters (chip temperature, sliding friction coefficient, tool geometry) and overall friction characteristics depicting the global response of the tool-chip interface. Sticking and sliding contact regimes are described.The overall friction characteristics of the tool are represented by two quantities: (i) the mean friction coefficient qualifies the global response of the tool rake face (tool edge excluded) and (ii) the apparent friction coefficient reflects the overall response of the entire tool face, the effect of the edge radius being included. When sticking contact is dominant the mean friction coefficient is shown to be essentially the ratio of the average shear flow stress along the sticking zone by the average normal stress along the contact zone. The dependence of overall friction characteristics is analyzed with respect to tool geometry and cutting conditions. The differences between mean friction and apparent friction are quantified. It is demonstrated that the evolutions of the apparent and of the mean friction coefficients are essentially controlled by thermal effects. Constitutive relationships are proposed which depict the overall friction characteristics as functions of the maximum chip temperature along the rake face. This approach offers a simple way for describing the effect of cutting conditions on the tool-chip interface response. Finally, the contact length and contact forces are analyzed. Throughout the paper, the consistency between numerical, analytical and experimental results is systematically checked.     

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.     

Metal cutting: Mechanics,surface physics and metallurgy

Orthogonal planing experiments have been carried out on 70/30 brass workpieces in the cutting speed range 0·3–150 ft/min. Measurements of chip radius, shear plane angle and the average coefficient of friction between chip and tool have been made and their inter-relationships are successfully explained in terms of a slip line field theory. For a non-hardening workpiece, chip shape is completely determined by the friction stress distribution between chip and tool, but three parameters are required to define this sufficiently, rather than the one, the coefficient of friction, of earlier theories.