陶瓷刀具切削镍基合金的三维数值模拟

为了揭示Sialon陶瓷刀具的切削力、切削温度和应力的变化规律,借助于有限元分析软件,建立了三维金属切削的有限元模型,模拟了Sialon陶瓷刀具切削镍基高温合金Inconel 718的切削过程,得到了切削力、切削温度及应力随刀具前角和切削速度变化的规律,计算出了Sianon陶瓷刀具切削Inconel 718时的合理前角是-8°,同时分析了刀具不同时刻切削温度和等效应力的分布规律。     

高速侧铣镍基合金Inconel 718切削力试验研究

采用整体式涂层硬质合金立铣刀对镍基合金Inconel 718进行了高速侧铣试验,研究了切削参数(包括切削速度、进给量、轴向切深和径向切深)的变化对切削力的影响。研究发现,随着轴向切深的增大,切削力先增大后减小,这主要是由于刀具在切削力的作用下产生了一定程度的弯曲变形和扭转变形,改变了刀具的整体刚度;随着切削速度、每齿进给量和径向切深的增大,切削力的值呈现线性增加的趋势,其中对切削力变化影响最大的是切削速度。     

基于切削技术的金刚石刀具磨损特征分析

金刚石刀具的磨损情况决定其使用寿命。用金刚石PCD刀具切削6061-T6镁铝合金工件,通过不同切削速度、切削深度、振动频率、刀具后角时的切削力及切削温度变化,研究不同刀具前后角、进给量、切削转速时的工件表面粗糙度及刀具磨损面积。结果表明:金刚石刀具的切削力和切削温度随切削速度、切削深度的增加而增大,随振动频率的增加而减小;刀具后角增大,金刚石刀具的切削力呈先下降而后缓缓上升趋势,但对切削温度的影响很小。当刀具前角为10°,刀具后角为8°,切削速度为0.46?m/s,切削深度为28?μm,进给量为0.10?mm/r,切削转速为4100?r/min,振动频率为22?kHz,切削振幅为9?μm时,金刚石刀具的磨损面积最小,磨损程度最低,使用寿命最长,但工件的表面粗糙度稍高。      

奥氏体不锈钢车削时刀具磨损对切削因素和表面质量的影响研究

研究了奥氏体不锈钢车削加工过程中刀具后刀面磨损对切削力、切削温度、粗糙度及残余应力影响规律。试验结果表明:当刀具后刀面磨损在一定范围内,F_x与F_z随磨损量的增加而显著增大,而F_y基本保持不变;温度随刀具后刀面磨损量增加而显著增大;工件的表面粗糙度随刀具后刀面磨损量增大而增大;当车刀后刀面磨损为0.167 mm时,工件加工表面的残余应力最大。     

基于ABAQUS高速切削Ti-6Al-4V切削状态的有限元仿真

文章基于Abaqus/Explicit的Johnson-Cook材料模型以及断裂准则模拟高速正交切削Ti-6Al-4V,仿真分析了切削速度、切削深度、刀具前角变化时对平均切削力以及锯齿状切屑形态的影响.研究结果表明:切屑锯齿化程度和齿距随切削速度和切削深度的增加而增大,随前角的增加而减小.平均切削力在切削速度为60m/min-180m/min时趋于平稳,随切削深度增加而增大,随前角增大而减小.     

不同磨损量PCBN刀具椭圆振动车削仿真研究

通过改变刀具磨损量建立具有不同磨损状态的PCBN刀具切削镍基高温合金Inconel 718的仿真模型,设置边界散热条件模拟浇注式切削液冷却环境,分别进行椭圆振动切削仿真和普通切削仿真。研究了具有不同磨损量的PCBN刀具对椭圆振动切削过程中切削力、切削温度、切屑形态的影响规律,并与普通切削进行对比。结果表明:在刀具磨损量相同的情况下,椭圆振动切削的切削力、切削温度的曲线斜率是大于0并且小于普通切削的,而切削力、切削温度是影响刀具使用寿命的重要因素,因此相比于普通切削,椭圆振动切削的刀具寿命更长;椭圆振动切削所形成的切屑弯曲半径比普通切削小,有利于断屑。此外该研究结果数据也可以为椭圆振动切削加工Inconel 718过程中PCBN刀具磨损的实时监测提供依据。     

切削条件对淬硬钢已加工表面白层形成的影响

高速切削淬硬钢已加工表面存在白层,对工件使用性能具有很大的影响,研究已加工表面白层对改善工件表面质量和切削加工性具有重要意义。通过使用PCBN刀具高速干硬切削GCr15钢和40Cr Ni Mo A钢实验,分析了高速干硬切削过程中已加工表面产生白层的条件,研究了切削速度、后刀面磨损量等切削参数以及材料含碳量对白层厚度的影响规律。研究表明:已加工表面白层厚度随切削速度提高呈现先增加后减小趋势,随刀具磨损量增加而增大;随着工件材料含碳量增加,白层厚度增大。     

CVD金刚石厚膜刀具切削参数对切削力及粗糙度影响的研究

为了探究CVD金刚石厚膜刀具切削参数(包括刀具后角、刀尖圆弧半径、切削速度、进给量和切削深度)对切削力和被加工表面粗糙度影响的初步规律,采用单因素方法进行了一系列CVD金刚石厚膜刀具车削仿真和试验研究。结果表明:AdvantEdge有限元仿真软件模拟切削力过程有一定的准确性;在试验参数范围内,随着刀具后角的增大,切削力和表面粗糙度都是先减小后增大,当后角为11°时,切削力和表面粗糙度值最小;随着刀尖圆弧半径的增大,切削力逐渐增大,而表面粗糙度则逐渐减小;随着切削速度的增大,切削力和表面粗糙度都是先增大后减小,当切削速度为90m/min时,切削力和表面粗糙度值最大;随着进给量的增大,切削力和表面粗糙度都显著增大;随着切削深度的增大,切削力和表面粗糙度都逐渐增大,但切削深度对表面粗糙度的影响较小。     

振动切削参数对纳米振动切削过程的影响

采用分子动力学的方法建立了金属钛的纳米振动切削模型,通过切削仿真研究了振动切削参数变化对整个振动切削过程的影响。研究发现:振动频率和振幅的增大会使接触率、切削力及切削温度的数值减小。切削速度增大会使接触率、切削力及切削温度升高,相比对切削力的改变,在切削速度小于100m/s的情况下对切削温度的影响效果更显著。刀具刃口半径的增大会使切削过程中已加工面的变质层厚度增加,表面粗糙度增大,切削力与切削温度的数值随刃口半径的增大而增加,当刃口半径跟切削厚度之比大于1时,背吃刀力及切削温度提升的速率更快。     

基于Deform-3D的65Mn硬态切削加工仿真研究

以淬硬钢65Mn为原料,采用有限元分析软件Deform?3D构建了硬态切削加工模型。模拟了不同切削速度下淬硬钢65Mn的车削加工过程,对车削加工的切削力、温度随切削速度的提高的变化以及工件表面应力变化的仿真结果给出了分析,为实现工艺参数的优化提供了指导。结果表明：硬态切削加工3个切削力中径向力Fy 最大,第二变形区的切削温度较高,硬态切削加工过程中工件表面应力呈现拉压交替变换且最终表现为压应力。     

A comparative study of the cutting forces in high speed machining of Ti–6Al–4V and Inconel 718 with a round cutting edge tool

Titanium alloy Ti–6Al–4V and nickel-based superalloy Inconel 718 have been widely employed in modern manufacturing. The published literature on high speed machining (HSM) of the two materials often involves different machining set-up, which makes it difficult to directly apply the research findings from one material to the other to select the most appropriate tool geometry and cutting conditions. A comparative experimental study of HSM of Ti–6Al–4V and Inconel 718 is conducted in this paper using the same machining set-up. The scope of this study is limited in high speed finish machining, where the tool edge geometry plays a significant role. The experimental set-up and the methods of measuring the cutting forces and the tool edge radius are introduced. A total of 40 orthogonal high speed tube-cutting tests were performed, involving five levels of cutting speeds and four levels of feed rates. Based on extensive experimental data, the similarities and differences between HSM of Ti–6Al–4V and Inconel 718 are quantitatively compared and qualitatively explained in terms of four quantities: (1) the cutting force F_c, (2) the thrust force F_t, (3) the resultant force R, and (4) the force ratio F_c/F_t. A total of 12 empirical regression relationships are obtained.     

镍基合金Inconel 718薄壁件铣削加工数控程序和切削参数优化

薄壁件加工过程因切削力波动较大可导致切削过程不平稳,需对加工工艺进行优化。建立了镍基合金Inconel718薄壁件铣削加工数控编程优化模型,模型由数控编程、材料数据库和数控加工仿真3个模块组成。在UG中建立工件实体模型,并生成相应NC加工代码;基于Power Law本构方程,考虑材料热力学动态性能和材料分离准则对切削力和切削温度的影响,采用有限元仿真软件AdvantEdge FEM获得镍基合金车削加工的切削力和切削温度等参数;将工件毛坯模型、NC加工代码、材料数据导入Production Module中,对加工过程进行优化。结果表明:利用优化后的数控程序进行加工,可减小切削力波动,有助于改善薄壁件加工过程中的稳定性。     

Mechanisms involved in the improvement of Inconel 718 machinability by laser assisted machining (LAM)

The aim of the present research work has been to gain a broader understanding of how or why laser assisted machining (LAM) improves machinability of Inconel 718, a hard-to-machine material of interest in the aeronautic industry. This has been accomplished by, first, running short run tests to determine the laser parameters and configuration for which highest force reductions are obtained and also to determine the effect of cutting parameters (feed, cutting speed and depth of cut) on force reduction. Secondly, long run tests have been performed in order to analyze process variables such as cutting forces, tool wear and surface roughness. Temperatures and hardness have been also measured in order to gain a broader perspective of the process.Experimental results have demonstrated that LAM improves machinability of Inconel 718 since machining forces and final surface roughness are reduced. The novelty reached with the present research work is the identification of three mechanisms associated to the laser heating as the responsible of this machinability improvement: material yield strength reduction, material base hardness reduction (only in precipitation hardened Inconel 718) and elimination of the work hardening generated in previous machining passes. The reduction of the work hardening leads also to a lower notch wear that limits the risk of sudden failure of the cutting tool and thus the wear mode is changed to flank wear, which leads to a controllable tool life and better surface roughness.     

切削Inconel718时新型陶瓷刀具JX-2-Ⅰ的切削性能研究

JX－2－Ⅰ是最新研制的碳化硅晶须（SiCw）增韧和碳化硅颗粒（SiCp）弥散增强氧化铝（Al2O3）新型陶瓷刀具。本文详细研究了该刀具加工Inconel718时的切削性能，结果表明，在低速干切时的刀具抗磨损能力为YG8＞JX－2－Ⅰ＞JX－1＞JX－2－Ⅱ；在105m／min的高速湿式切削时，JX－2－Ⅰ的切削性能与JX－1差不多，但是在42m／min的速度时JX－2－Ⅰ的切削性能好于JX－1（Al2O3＋SiCw）。同时发现在用JX－2－Ⅰ中高速切削Inconel718时必须使用冷却液。由于切削温度对工件材料加工硬化的影响，以及对工件材料高温强度屈服拐点的影响而存在一个切削速度的最佳选取范围。SEM分析表明，刀具磨损的主要形式是后刀面磨损、边界磨损、切深沟槽磨损和前刀面月牙洼磨损；刀具磨损的主要机理是粘结磨损、磨粒磨损和塑性变形磨损。     

An experimental study of tool wear and cutting force variation in the end milling of Inconel 718 with coated carbide inserts

Inconel 718 is a difficult-to-cut nickel-based superalloy commonly used in aerospace industry. This paper presents an experimental study of the tool wear propagation and cutting force variations in the end milling of Inconel 718 with coated carbide inserts. The experimental results showed that significant flank wear was the predominant failure mode affecting the tool life. The tool flank wear propagation in the up milling operations was more rapid than that in the down milling operations. The cutting force variation along with the tool wear propagation was also analysed. While the thermal effects could be a significant cause for the peak force variation within a single cutting pass, the tool wear propagation was believed to be responsible for the gradual increase of the mean peak force in successive cutting passes.     

Cutting temperature of ceramic tools in high speed machining of difficult-to-cut materials

This paper deals with an experimental and analytical investigation into the different factors which influence the temperature distribution on Al₂O₃---TiC ceramic tool rake face during machining of difficult-to-cut materials, such as case hardened AISI 1552 steel (60–65 Rc) and nickel-based superalloys (e.g. Inconel 718). The temperature distribution was predicted first using the finite element analysis. Temperature measurements on the tool rake face using a thermocouple based technique were performed and the results were verified using the finite element analysis. Experiments were then performed to study the effect of cutting parameters, different tool geometries, tool conditions, and workpiece materials on the cutting edge temperatures. Results presented in this paper indicate that for turning case hardened steel, increasing the cutting speed, feted, and depth of cut will increase the cutting edge temperature. On the other hand, increasing the tool nose radius, and angle of approach reduces the cutting edge temperature, while increasing the width of the tool chamfer will slightly increase the cutting ege temperature. As for the negative rake angle, it was found that there is an optimum value of rake angle where the cutting edge temperature was minimum. For the Inconel 718 material, it was found that the cutting edge temperature reached a minimum at a speed of 510 m/min, and feed of 1.25 mm/rev. However, the effect of the depth of cut and tool nose radius was almost the same as that determined in the turning of case hardened steel. It was also observed in turning Inconel 718 with ceramic tools that, cutting forces and different types of tool wear were reduced with increasing the feed.     

High-speed rotary cutting of difficult-to-cut materials on multitasking lathe

This paper aims to realize the high-speed rotary dry cutting of an Inconel 718 at 500 m/min on a multitasking lathe which has an additional milling spindle with an X/Y/Z-axis and inclination control. A series of experiments were conducted and are discussed with respect to the tool face temperature analysis by FEM. It was verified that it is necessary to select an optimum inclination angle, tool rotation speed and tool diameter so as to enable the main cutting force direction to align with the highest rigidity direction of an applied rotary tool. Under preferable cutting conditions, the average tool rake face temperature measured by a thermograph camera was about 300 °C even at a high cutting speed of 500 m/min under dry cutting conditions, and the tool wear decreased dramatically compared with the conventional tools.     

Dry machining of Inconel 718, workpiece surface integrity

In the machining of Inconel 718, nickel based heat resistant superalloy and classified difficult-to-cut material, the consumption of cooling lubricant is very important. To reduce the costs of production and to make the processes environmentally safe, the goal is to move toward dry cutting by eliminating cutting fluids. This goal can be achieved by using coated carbide tool and by increasing cutting speed.The present paper firstly reviews the main works on surface integrity and especially residual stresses when machining Inconel 718 superalloy. It focuses then on the effect of dry machining on surface integrity. Wet and dry turning tests were performed at various cutting speeds, with semi-finishing conditions (0.5 mm depth of cut and 0.1 mm/rev feed rate) and using a coated carbide tool. For each cutting test, cutting force was measured, machined surface was observed, and residual stress profiles were determined. An optimal cutting speed of 60 m/min was determined, and additional measurements and observations were performed. Microhardness increment and the microstructure alteration beneath the machined surface were analysed. It is demonstrated that dry machining with a coated carbide tool leads to potentially acceptable surface quality with residual stresses and microhardness values in the machining affected zone of the same order than those obtained in wet conditions when using the optimised cutting speed value; in addition, no severe microstructure alteration was depicted.     

Surface topography irregularities generated by broaching

Surface topography irregularities generated by broaching are analysed. Experimental tests were carried out on three workpiece materials: AISI 1045, Ti-6Al-4V, and Inconel 718, varying the cutting speed, rise per tooth, and rake angle. The experimental results combined with numerical simulation demonstrate that surface topography irregularities result from mechanical rather than thermal effects. Higher surface topography variations are obtained when the force magnitude increases, and when its direction is more perpendicular to the machined surface. Additionally, the Young's modulus of both the workpiece and tool materials plays a fundamental role in topography quality, reducing irregularities when the Young's modulus is increased.     

Modelling the correlation between cutting and process parameters in high-speed machining of Inconel 718 alloy using an artificial neural network

An artificial neural network (ANN) model was developed for the analysis and prediction of the relationship between cutting and process parameters during high-speed turning of nickel-based, Inconel 718, alloy. The input parameters of the ANN model are the cutting parameters: speed, feed rate, depth of cut, cutting time, and coolant pressure. The output parameters of the model are seven process parameters measured during the machining trials, namely tangential force (cutting force, F_z), axial force (feed force, F_x), spindle motor power consumption, machined surface roughness, average flank wear (VB), maximum flank wear (VB_max) and nose wear (VC). The model consists of a three-layered feedforward backpropagation neural network. The network is trained with pairs of inputs/outputs datasets generated when machining Inconel 718 alloy with triple (TiCN/Al₂O₃/TiN) PVD-coated carbide (K 10) inserts with ISO designation CNMG 120412. A very good performance of the neural network, in terms of agreement with experimental data, was achieved. The model can be used for the analysis and prediction of the complex relationship between cutting conditions and the process parameters in metal-cutting operations and for the optimisation of the cutting process for efficient and economic production.