航空难加工材料切削刀具磨损与剩余寿命预测研究进展

航空制造领域因轻量化、强度等特殊的应用需求,大量使用钛合金、镍基合金等难切削材料,刀具磨损速率快,刀具过度磨损会影响产品质量,在保证产品质量的前提下,为了充分发挥刀具使用价值,亟需监测刀具磨损状态和预测刀具剩余寿命。针对刀具剩余寿命预测的定义、分类和主要预测方法进行了阐述,同时,刀具磨损监测作为刀具寿命预测的基础和先决条件,简述了其重要的流程和常见模型。刀具剩余寿命预测模型主要包括基于物理模型的预测、基于数据驱动的预测和混合预测三大类,对不同预测方法的优缺点和适用场景进行总结,并讨论了刀具剩余寿命预测的未来研究方向。     

钛合金铣削加工刀具磨损有限元预测分析

钛合金Ti6Al4V因其优良的综合性能在航空航天领域有着广泛的应用。然而,在钛合金切削过程中,极易出现刀具磨损现象。目前尚缺乏钛合金加工用刀具寿命预测的有效手段和方法。针对这一问题,基于刀具在铣削工作过程中受到的热力耦合作用,利用Fick扩散定律揭示了刀具扩散磨损机理,构建刀具磨损模型;利用有限元仿真软件Advant Edge的二次开发技术,将刀具磨损模型嵌入到有限元模型中,进行刀具磨损的预测;进而借助刀具寿命试验,验证了刀具磨损模型的可靠性。     

基于改进EGM(1,1)的刀具磨损预测

刀具磨损及寿命预测一直是刀具管理研究的重要领域,但由于加工工艺、使用强度及环境因素的极度未确知性,很难取得对刀具寿命的准确判断,因而增加了机床或工件损坏的风险,所以需要构建模型实现对磨损程度的有效预测。本文首先通过一定条件下的刀具磨损实验,测量出刀具在相同工作时间内的磨损值,然后采用新信息优先的新陈代谢EGM(1,1)模型对特定条件下的数据序列进行拟合与预测,并与传统EGM(1,1)进行比较。结论发现新陈代谢EGM(1,1)模型具有更高的预测精度、更小的拟合误差,对提高刀具磨损及寿命预测的准确性具有重要方法意义。     

硬质合金钻头钻削球墨铸铁的切削性能研究

在观察磨损形貌的基础上,分析硬质合金钻头在加工球墨铸铁时的主要磨损形式。在设定轴向力极值、将磨损标准量化之后,推算出刀具寿命预测公式,并得出结论,在钻削QT600牌号的球墨铸铁曲轴时,硬质合金钻头的主要磨损形式为钻尖磨损,相应的轴向力极限推荐值为5500N。除了大长径比和大直径钻头以外,对于大部分钻头而言,刀具寿命预测公式与实际寿命误差在10%以内。     

涂层硬质合金刀具高速车削300M刀具磨损机理研究

以在飞机、汽车、轮船等领域的关键承力件上广泛应用的超高强度合金钢300M作为研究对象,采用涂层硬质合金刀具进行高速干车削加工,并对切屑变形、刀具寿命及刀具磨损机理进行分析。研究表明:高速切削300M时,切屑的塑性变形严重;涂层刀具主要的磨损形式为正常的前、后刀面磨损,以及非正常的剥落和崩刃;刀具在稳定磨损阶段形成了次生粘结层起着隔热、减摩的作用,有效提高了刀具寿命,但在急剧磨损阶段,大块状的粘结、崩刃、涂层剥落、微裂纹等致使刀具磨损加剧;高速车削300M涂层硬质合金刀具主要的磨损机理为粘结磨损、磨粒磨损、涂层剥落、微崩刃、微裂纹。该研究可望在高性能涂层刀具设计、刀具寿命预测等方面推广应用。     

基于响应面法的微小型车铣加工刀具磨损分析

针对刀具磨损与刀具寿命的预测问题,通过响应曲面法建立车铣切削参数与磨损量之间的回归模型,寻求最优车铣工艺参数,更为直观有效地观察切削参数与刀具磨损之间的变化关系,利用响应面回归模型开展刀具磨损的预测与评估。     

超大直径盾构机刀具磨损规律及布置方法研究

针对超大直径盾构机工况的特殊性,研究了刀盘上刀具的磨损规律。依据建立的刀具磨损模型,预测刀具的掘进寿命,采用等磨损布置方法,使超大直径盾构机刀具的布置更加合理,为超大直径盾构的技术研究提供依据与参考。     

高速铣削刀具磨损寿命实验及建模研究

为研究高速铣削中刀具磨损寿命与切削参数的关系,通过正交实验获得了不同切削用量下的刀具磨损寿命数据,并用正交直观法分析了各切削参数对刀具磨损寿命的影响程度,以及刀具磨损寿命随切削用量的变化趋势.在多元线性回归分析的基础上建立了刀具磨损寿命与切削参数的经验模型,并用显著性检验分析了模型的拟合程度以及各切削参数对刀具磨损寿命的影响程度.研究结果为切削参数优化提供了依据.     

刀具磨损在线检测及刀具寿命实时跟踪技术在FMS中应用

刀具磨损在线检测和刀具寿命实时跟踪是柔性制造系统(FMS)的关键技术之一,通过分析刀具磨损在线检测原理,形成了适合于FMS刀具磨损检测的方案和具体实施办法,通过探讨刀具寿命的主要影响因素,提出了使用雷尼绍NC4非接触式刀具磨损检测系统进行刀具寿命监控的措施,在此基础上,开发了刀具寿命跟踪管理系统。研究成果提高了刀具磨损检测和刀具寿命管理的准确性与控制效率,有效提升了FMS工件加工合格率和加工精度。     

基于数据驱动的铣削刀具寿命预测研究

建立了一种基于轨迹相似性和支持向量回归机的集成预测模型,可以预测刀具的寿命。对试验采集到的信号进行了时域和小波分析,研究了信号特征量与刀具磨损之间的关系。计算了45个特征量与刀具磨损之间的相关系数,最终选择5个特征向量作为预测模型的输入向量。样本刀具1、2和3在稳定加工阶段的寿命预测精度分别为88.5%,87.5%和90.5%。并同其他模型进行了对比,结果表明,所提出的集成模型在刀具剩余使用寿命预测方面预测精度更优。     

Suppression of notch wear of a whisker reinforced ceramic tool in air-jet-assisted high-speed machining of Inconel 718

This paper describes the notch and flank wear specific to a SiC whisker reinforced alumina tool in air jet assisted (AJA) turning of nickel-base superalloy Inconel 718 at high cutting speeds. An AJA machining experiment has revealed that the air jet applied to the tool tip in addition to coolant dramatically reduces the depth-of-cut notch wear. As a result, the width of flank wear, but not the size of notch wear, determined the life of a ceramic tool in AJA machining of Inconel 718. This is a reason for the large extension and small variation of the tool life when high speed AJA machining is adopted. The maximum tool life length reached 2160 m at a cutting speed of 660 m/min under the given cutting conditions. Finally, the mechanisms of the notch and flank wear of a SiC whisker reinforced alumina tool in AJA machining are discussed from the viewpoints of tribochemical reactions and tool wear anisotropy.     

Improving machinability of Inconel 718 with a new hybrid machining technique

In this paper, by joining three non-traditional machining methods — plasma-enhanced machining, cryogenic machining, and ultrasonic vibration assisted machining — a new hybrid machining technique for machining of Inconel 718 is presented. Cryogenic machining reduces the temperature in the cutting zone, and therefore decrease tool wear and increases tool life, while plasma-enhanced machining helps to increase the temperature in the workpiece to make it softer. Also, applying ultrasonic vibrations to the tool helps to improve cutting quality and to prolong tool life by lowering, mainly, the cutting force and improving the dynamic cutting stability. This study experimentally investigates the effect of cutting parameters on cutting performance in the machining of Inconel 718 and compares the results of hybrid machining and conventional machining (CM). It is found that the hybrid method results in better surface finish and improves tool life in hard cutting at low cutting speeds as compared to the CM method.     

激光超声复合切削硬质合金的刀具磨损及其对工件表面质量的影响

基于激光加热辅助切削和超声椭圆振动切削提出了激光超声复合切削加工工艺。采用聚晶立方氮化硼(PCBN)刀具对YG10硬质合金进行了常规切削,超声椭圆振动切削,激光加热辅助切削和激光超声复合切削对比试验。检测了刀具磨损量、刀具磨损形貌、工件表面粗糙度以及工件表面形貌,并通过扫描电镜(SEM)对刀具磨损区域进行了能谱分析,同时研究了激光超声复合切削硬质合金时PCBN刀具的磨损及其对工件表面质量的影响。最后,与常规切削、超声振动切削及激光加热辅助切削进行了对比试验。结果表明:激光超声复合切削时刀具使用寿命显著增加,加工后的工件表面粗糙度平均值分别降低了79%、60%和64%,且工件表面更加平整光滑。激光超声复合切削硬质合金时,PCBN刀具的前刀面磨损表现为平滑且均匀的月牙洼磨损,后刀面磨损表现为较窄的三角形磨损带和较浅的凹坑和划痕;刀具的失效机理主要为黏接磨损、氧化磨损和磨粒磨损的综合作用。     

The Effect of Argon-Enriched Environment in High-Speed Machining of Titanium Alloy

A major factor hindering the machinability of titanium alloys is their tendency to react with most cutting tool materials, thereby encouraging solution wear during machining. Machining in an inert environment is envisaged to minimize chemical reaction at the tool-chip and tool-workpiece interfaces when machining commercially available titanium alloys at higher cutting conditions. This article presents the results of machining trials carried out with uncoated carbide (ISO K10 grade) tools in an argon-enriched environment at cutting conditions typical of finish turning operations. Comparative trials were carried out at the same cutting conditions under conventional coolant supply. Results of the machining trials show that machining in an argon-enriched environment gave lower tool life relative to conventional coolant supply. Nose wear was the dominant tool-failure mode in all the cutting conditions investigated. Argon is a poor conductor of heat; thus, heat generated during machining tends to concentrate in the cutting region and accelerate tool wear. Argon also has poor lubrication characteristics, leading to increasing friction at the cutting interfaces during machining and an increase in cutting forces required for efficient shearing of the workpiece.     

高速干切削铁基粉末冶金零件时细晶粒硬质合金刀具的切削性能研究

用细晶粒硬质合金刀具进行了铁基粉末冶金零件的高速干切削试验。研究了切削参数与刀具耐用度以及加工表面粗糙度的关系,给出了刀具的主要磨损形态,通过能谱分析研究了刀具的磨损机理。结果表明:所选用细晶粒硬质合金刀具具有较高的刀具耐用度和较好的加工表面粗糙度,适合于铁基粉末冶金的加工;细晶粒硬质合金的主要磨损形态是前刀面的月牙洼磨损;主要磨损机理是扩散磨损、粘结磨损。     

氮化碳涂层刀具干式切削研究

通过与传统湿式切削加工的对比,介绍了金属干式切削加工的技术优点和发展趋势,分析了氮化碳涂层刀具的特点。通过干式切削淬火钢的试验,分析了涂层刀具干式切削加工的技术特点及刀具的磨损机理。试验表明,氮化碳涂层能够很好地保证干式切削的进行,涂层一旦磨损,刀具很快磨损;切削参数中切削速度对刀具寿命影响最大。     

Tool wear mechanisms in the machining of Nickel based super-alloys: A review

Nickel based super-alloys are widely employed in aircraft engines and gas turbines due to their high temperature strength, corrosion resistance and, excellent thermal fatigue properties. Conversely, these alloys are very difficult to machine and cause rapid wear of the cutting tool, frequent tool changes are thus required resulting in low economy of the machining process. This study provides a detailed review of the tool wear mechanism in the machining of nickel based super-alloys. Typical tool wear mechanisms found by different researchers are analyzed in order to find out the most prevalent wear mechanism affecting the tool life. The review of existing works has revealed interesting findings about the tool wear mechanisms in the machining of these alloys. Adhesion wear is found to be the main phenomenon leading to the cutting tool wear in this study.     

钛合金零件高速铣削刀具磨损的试验研究

高速铣削钛合金时,由于切削区内的切削温度高,加剧了刀具的磨损。通过对钛合金TC4的高速铣削实验,得出带TiA lN涂层的硬质合金刀具切削钛合金TC4时的刀具磨损的变化规律和刀具耐用度公式。通过对刀具磨损特性的分析,研究结果主要是刀具表面层的粘结相Co在高温下丧失对WC颗粒的结合强度,磨损机理以高温下的粘结层撕裂磨损为主。     

Survival life analysis applied to tool life estimation with variable cutting conditions when machining titanium metal matrix composites (Ti-MMCs)

A survival analysis methodology is employed through a novel approach to model the progressive states of tool wear under different cutting conditions during machining of titanium metal matrix composites (Ti-MMCs). A proportional hazards model (PHM) with a Weilbull baseline is developed to estimate the reliability and hazard functions of the cutting inserts. A proper criterion is assigned to each state of tool wear and used to calculate the tool life at the end of each state. Accounting for the machining time and different stages of tool wear, in addition to the effect of cutting parameters, an accurate model is proposed. Investigating the results obtained for different states, it was shown that the evolution of the time-dependent phenomena, such as different tool wear mechanisms, throughout the whole machining process were also reflected in the model. The accuracy and reliability of the predicted tool lives were experimentally validated. The results showed that the model gives very good estimates of tool life and the critical points at which changes of states take place.     

EFFECT OF COOLANT PRESSURE,NOZZLE DIAMETER,IMPINGEMENT ANGLE AND SPOT DISTANCE IN HIGH PRESSURE COOLING WITH NEAT OIL IN TURNING Ti-6AL-4V

Though titanium alloys are being increasingly sought in a wide variety of engineering and biomedical applications, their manufacturability, especially machining and grinding imposes lot of constraints. Titanium alloys are readily machinable provided the cutting velocity is in the range of 30–60 m/min. To achieve higher productivity, if the cutting velocity is enhanced to 60–120 m/min and beyond, rapid tool wear takes place diminishing the available tool life. Tool wear in machining of titanium alloys is mainly due to high cutting zone temperature localised in the vicinity of the cutting edge and enhanced chemical reactivity of titanium with the tool material. Rapid tool wear encountered in machining of titanium alloys is a challenge that needs to be overcome. High pressure cooling in machining is a very promising technology for enhancing tool life and productivity via appropriate cooling and lubrication. The present investigation is an attempt to study the effects of jet application parameters, i.e., coolant pressure, angle of impingement of the jet, spot distance and nozzle diameter on tool wear and chip morphology and to compare the effectiveness while turning Ti-6Al-4V bars under high pressure cooling with neat oil. Results indicated that at a cutting speed of 85 m/min and feed of 0.2 mm/rev, high pressure cooling provided a tool life of 24 min vis-à-vis 12 min under cryogenic cooling.