TC4表面精整车削三维仿真与验证

为了分析无心车床精整车削钛合金线材过程中切削速度、进给速度、切削深度对切屑形貌、切削力和残余应力的影响,使用仿真模拟软件ABAQUS建立基于无心车床的三维有限元精整车削模型,并且通过试验设计与仿真结果进行对比分析。车削钛合金的过程中,高转速会形成较短的C形屑,有利于切屑的分离与断裂。由于主轴转速的增加,工件与刀具之间摩擦力降低,切削力随着主轴转速的增加而减小。由于进给速度增加,每转进给量随之增加,工件去除量增加,随着进给速度的增加切削力也随之增加。由于切削深度增加,切削去除量不断增加,因此切削力随切削深度的增大而增大。车削钛合金的过程中需要提高转速来降低切削力,有利于切削过程。同时进给速度较小时,易于生成C形屑,有利于车削过程。     

切削用量对车削Ti6Al4V切削力影响的研究

通过硬质合金刀具高速干切削Ti6Al4V钛合金的试验,分析了切削用量对切削力的影响.试验结果表明:在切削三要素中,切削深度和进给量对切削力的影响较大,切削速度对于切削力的影响较小.进给量对背向力的影响最大,切削深度对进给力的影响最大.刀尖圆弧半径对于进给力和背向力的变化规律有重要影响.     

钛合金TC21铣削切削力预测实验研究

基于正交试验,针对钛合金TC21难加工性,研究了铣削工艺参数切削速度、每齿进给、轴向切深和径向切深对切削力的影响规律;借助数理统计和回归分析实验理论和方法,建立了钛合金TC21切削力的预测模型,并对该模型及回归系数进行显著性检验。研究表明,在高速铣削TC21钛合金过程中,切削力随切削速度的增大而减小,随每齿进给、轴向切深、径向切深的增大而增大;切削深度、每齿进给量对切削力的影响较大,切削速度和径向切深对切削力的影响不显著;经切削验证,建立的切削力预测模型是高度显著的。     

CVD涂层刀具高速铣削大理石切削力研究

选定切削参数(切削速度、进给速度、切削深度)设计正交试验,进行CVD氮化钛涂层刀具高速铣削大理石切削力试验,利用测力仪测出各组试验的切削力信号图,分析信号图特征得出切削力值,并记录各组切削力试验结果。分析单一切削参数(切削速度、进给速度,切削深度)对切削力变化的影响规律。采用最小二乘法原理对切削力经验公式回归系数进行参数估计,并对经验公式进行相关性检验,检验结果表明显著性很高。最终通过试验结果得出:切削力随着进给速度和切削深度的增加而增大,随着切削速度的增加而减小;并且切削深度对切削力影响最大,切削速度次之,进给速度对切削力的影响最小。     

基于正交试验的高速切削钛合金切削力研究

随着钛合金在各行业的广泛应用,钛合金的高速切削加工技术成为航天航空工业及其他制造业中的难题之一。切削力是研究切削过程的重要物理量之一,其大小和变化对工件加工品质、刀具磨损和寿命等都具有影响。本文以钛合金Ti6Al4V为研究对象,用正交试验的方法分析了切削速度、进给量和背吃刀量三个因素对切削力的影响,结果表明:径向力、切向力、轴向力都是随切削速度增大而减小,随进给量和背吃刀量的增大而增大,切削用量的变化导致各向切削力与切削合力的变化趋势基本一致;背吃刀量对切削力影响最大,进给量次之,切削速度最小;三个方向力中,轴向力最小,径向力次之,切向力最大。     

液氮低温切削钛合金实验研究

针对钛合金难加工特点,将液氮作为冷却介质直接喷向切削区进行钛合金TC4低温车削加工,测量其切削力、表面粗糙度和刀具磨损,并与干切削在相同实验条件下对比,分析低温切削对钛合金的影响。实验结果表明:低温切削钛合金,主切削力有所增大,但进给方向力减小,刀具磨损状况与表面质量得到改善,断屑相对容易。     

刀具角度对TC4钛合金切削力的影响

基于Deform建立了硬质合金刀具切削TC4钛合金时的仿真模型,通过切削试验对仿真模型的主切削力进行了验证,并利用该模型对刀具角度与切削力之间的关系进行了研究。研究结果表明:仿真所得到的主切削力与试验测得主切削力相差小于10%,仿真模型可靠性较高,可用于TC4钛合金切削力的研究。通过仿真研究得到,在一定范围内,随着刀具前角的增大,主切削力和进给力明显减小;刀具后角的增大对主切削力影响不明显,但对进给力的影响比较明显。     

超硬刀具高速切削钛合金时的切削力研究

基于锯齿切屑相关理论,以单位切削力、切削力静态分量和动态分量为指标,对PCD/PCBN两种超硬刀具高速切削TC4钛合金的切削力进行对比研究。研究发现：两种超硬刀具高速切削TC4钛合金时,单位切削力大小基本相同,且均随切削速度增大而整体呈略微增加趋势,均随进给量、背吃刀量的增大而减小;单位切削力大小取决于锯齿形切屑基块内材料应变及应变率强化作用和温度弱化作用。两种超硬刀具切削力静态分量大小基本相同,且均随切削速度的增大整体呈略微增大趋势,均随进给量和背吃刀量的增大而增大。两种超硬刀具的切削力动态分量均随切削速度的增大而减小,均随进给量和背吃刀量的增大而增大。PCD刀具的切削力动态分量大于PCBN刀具;切削力动态分量大小与靠近刀尖处发生热塑剪切失稳切削层材料的体积和温度有关。     

镍基激光熔覆合金涂层高速铣削切削力试验研究

为研究高速铣削镍基激光熔覆合金涂层切削加工性能,探明高速铣削时铣削参数对切削力的影响规律。以Q690为基材,镍60合金粉末为熔覆材料制备铣削试件。采用硬质合金立铣刀对熔覆合金涂层进行高速铣削试验,利用单因素试验法,研究分析高速铣削下铣削深度、进给速度和主轴转速对镍基熔覆合金切削力的影响规律。结果表明,高速铣削镍基熔覆合金时径向切削力F_x、轴向切削力F_z和主切削力F_y均随铣削深度和进给速度的增大而增大,随主轴转速的增大而减小;三个方向的分力中主切削力F_y最大;三个铣削参数对切削合力F_合的影响显著性为切削深度a_p>进给量v_f>主轴转速s。     

刀具参数对Nomex蜂窝芯超声切削性能影响分析

直刃尖刀是一种常用的切削Nomex蜂窝芯的超声切削刀具,其刀具参数直接影响着Nomex蜂窝芯的切削性能.基于ABAQUS有限元分析软件,建立了Nomex蜂窝芯超声切削力热耦合分析的三维有限元模型.采用单因素法,研究刀具长度、刃角和厚度等参数对进给力和切削温度的影响.分析结果表明:在Nomex蜂窝芯超声切削过程中进给力和切削温度均随着刀具长度的增大而减小,随着刀具厚度和刀具刃角的增大而增大.同时通过建立Nomex蜂窝芯超声切削过程中进给力和切削温度的数学模型,分析刀具参数对进给力和切削温度的影响规律,验证了有限元分析结果的正确性.     

Some studies on hard turning of AISI 4340 steel using multilayer coated carbide tool

Hard turning with multilayer coated carbide tool has several benefits over grinding process such as, reduction of processing costs, increased productivities and improved material properties. The objective was to establish a correlation between cutting parameters such as cutting speed, feed rate and depth of cut with machining force, power, specific cutting force, tool wear and surface roughness on work piece. In the present study, performance of multilayer hard coatings (TiC/TiCN/Al₂O₃) on cemented carbide substrate using chemical vapor deposition (CVD) for machining of hardened AISI 4340 steel was evaluated. An attempt has been made to analyze the effects of process parameters on machinability aspects using Taguchi technique. Response surface plots are generated for the study of interaction effects of cutting conditions on machinability factors. The correlations were established by multiple linear regression models. The linear regression models were validated using confirmation tests. The analysis of the result revealed that, the optimal combination of low feed rate and low depth of cut with high cutting speed is beneficial for reducing machining force. Higher values of feed rates are necessary to minimize the specific cutting force. The machining power and cutting tool wear increases almost linearly with increase in cutting speed and feed rate. The combination of low feed rate and high cutting speed is necessary for minimizing the surface roughness. Abrasion was the principle wear mechanism observed at all the cutting conditions.     

航空钛合金高效插铣加工实验与多目标优化研究

钛合金整体叶盘是航空发动机的重要零部件,结构复杂,加工难度大。插铣加工因其轴向承受能力强和刚性大等特性,非常适合加工钛合金整体叶盘这类难加工、结构复杂的零部件。针对钛合金插铣加工效率的问题,采用响应曲面法设计插铣实验,建立切削力经验模型,以切削力和材料去除率为目标,采用NSGA-II算法进行多目标优化获得Pareto最优解。研究表明:切削力随主轴转速的增加而缓慢减小,随切削宽度、切削步距和每齿进给量的上升而增加;与实验初始参数组合相比,优化后的材料去除率提高了81.19%,而切削力减小了23.68%,达到了本研究的高效加工目标。     

An experimental investigation on the process parameters influencing machining forces during milling of carbon and glass fiber laminates

Milling is the most feasible machining operation for producing slots and keyways with a well defined and high quality surface. Milling of composite materials is a complex task owing to its heterogeneity and the associated problems such as surface delamination, fiber pullout, burning, fuzzing and surface roughness. The machining process is dependent on the material characteristics and the cutting parameters. An attempt is made in this work to investigate the influencing cutting parameters affecting milling of composite laminates. Carbon and glass fibers were used to fabricate laminates for experimentations. The milling operation was performed with different feed rates, cutting velocity and speed. Numerically controlled vertical machining canter was used to mill slots on the laminates with different cutting speed and feed combinations. A milling tool dynamo meter was used to record the three orthogonal components of the machining force. From the experimental investigations, it was noticed that the machining force increases with increase in speed. For the same feed rate the machining force of GFRP laminates was observed to be very minimal, when compared to machining force of CFRP laminates. It is proposed to perform milling operation with lower feed rate at higher speeds for optimal milling operation.     

金刚石圆锯片锯解花岗石切削力及参数优化的实验研究

基于金刚石圆锯片锯解花岗石的切削力正交实验研究,对切削速度、进给速度和背吃刀量三因素影响切削力的显著性进行极差分析,得出切削力Fx、Fy、Fz随切削速度的增大而减小,随进给速度和背吃刀量的增大而增大的变化趋势。通过回归分析建立切削力数学模型并进行量化分析,得出切削速度对切削力Fx的影响要比对切削力Fy和Fz大、背吃刀量对切削力Fz的影响要比对切削力Fx和Fy大的结论,并以材料去除率和切削力为评价指标对工艺参数进行优化,得到用于生产加工的最佳工艺参数组合。     

Investigations of flank wear, cutting force, and surface roughness in the machining of Al-6061�CTiB2 in situ metal matrix composites produced by flux-assisted synthesis

This paper presents the results of an experimental investigation on the machinability of in situ Al-6061?CTiB₂ metal matrix composite (MMC) prepared by flux-assisted synthesis. These composites were characterized by scanning electron microscopy, X-ray diffraction, and micro-hardness analysis. The influence of reinforcement ratio of 0, 3, 6, and 9?wt.% of TiB₂ on machinability was examined. The effect of machinability parameters such as cutting speed, feed rate, and depth of cut on flank wear, cutting force and surface roughness were analyzed during turning operations. From the test results, we observe that higher TiB₂ reinforcement ratio produces higher tool wear, surface roughness and minimizes the cutting forces. When machining the in situ MMC with high speed causes rapid tool wear due to generation of high temperature in the machining interface. The rate of flank wear, cutting force, and surface roughness are high when machining with a higher depth of cut. An increase in feed rate increases the flank wear, cutting force and surface roughness.     

GH4169高温合金切削仿真分析及工艺参数优化

以GH4169高温合金为切削仿真分析对象,采用田口法、信噪比分析、极差分析和交互作用分别得出切削深度对切削力影响最大,切削速度对切削温度影响最大,切削温度随着切削速度和进给量的增大而略有增大,切削力随着切削深度和进给量的增大而显著增大,切削力增大会使切削温度升高。运用多目标遗传优化算法,得出切削参数的帕累托最优解集,优化结果和仿真试验结果误差率小于5%。     

基于ABAQUS的钛合金铣削力的模拟分析

为了研究钛合金在铣削过程中切削力随着切削参数的变化规律,建立了三维斜角切削有限元模型。通过对材料本构模型,刀—屑接触摩擦模型和切屑分离准则等关键环节建模,采用通用有限元求解器ABAQUS/Ex-plicit对钛合金Ti6Al4V的斜角切削过程进行了模拟,获得了切削速度v、切削深度ap和每齿进给量fz对切削力的变化趋势及影响程度。模拟结果表明:切削力随着切削深度ap和每齿进给量fz的增大而增大,而随着切削速度增大切削力波动很小。切削深度对切削力的影响最大,进给量次之,切削速度对切削力的影响最小。该模型可以为切削参数的合理选择提供参考。     

高速加工时各切削参数对切削力影响的模拟研究

切削力是切削过程中重要的物理参数之一。本文应用数值模拟,对高速切削加工过程中切削参数(切削速度、进给量、切削深度)对切削力的影响进行了研究,给出了切削力随切削速度、进给量、切削深度的变化规律,对优化高速切削工艺及建立高速切削数据库具有指导意义。     

The investigation of mechanism of serrated chip formation under different cutting speeds

Chip type is determined by the coupled effects of workpiece material property, cutting speed, uncut chip thickness, feed rate, and tool edge geometry. The understanding of chip formation plays a critical role in studying surface integrity and optimization of machining process variables. Serrated chip, one of the major important chip type, is usually formed in hard cutting at high speed. In this study, a new analytical model has been proposed to better understand the formation of serrated chip, and the simulations have been acquired using ABAQUS/Explicit in machining AISI 1045 during different speeds (from 60 to 6000 m/min). The workpiece material property is modeled with the Johnson-Cook model, and the experiments have been conducted with AISI 1045 during speeds from 60 to 1200 m/min. It has been shown that flow stress is influenced simultaneously by the strain rate hardening and temperature softening. When the speed reaches very high, the temperature softening will fail, and the strain rate hardening will play a more important role. Also, it can be found that the hardening ratio increases when the cutting speed rises. The results of the simulations and experiments correlated well. The cutting force and thrust force both decrease as the cutting speed increases, and the difference between them will shrink when the machining speed reaches a high level.     

Development of cutting force prediction model for carbon fiber reinforced polymers based on rotary ultrasonic slot milling

Carbon fiber reinforced polymers (CFRP) have got widely increased applications in aviation, defense and other industries due to their properties of high specific strength/stiffness, high corrosion resistance and low-thermal expansion. The issues like excessive cutting forces and machining damages are encountered in machining due to heterogeneity, anisotropy and low heat dissipation of these materials. The cutting forces are required to be predicted/minimized through modeling. In this article, the novel axial and feed cutting force model has been developed and validated through rotary ultrasonic slot milling of CFRP composites. The variations less than 10% have been found between the measured and corresponding simulated values of the cutting forces. However, some higher variations have also been observed in the few cases mainly due to heterogeneity and anisotropy of such material. The cutting depth is a significant parameter for axial and feed forces, while the feed rate is significant for the axial force. Both the forces decreased with the increase of spindle speed, while they increased with the increase of feed rate and cutting depth. The developed models have been found to be robust and can be applied to optimize the cutting forces for such materials at the industry level.