钛合金高速旋转超声椭圆振动侧铣削切屑特征和刀具磨损研究

难加工材料钛合金在采用传统铣削方式时,随着切削速度的增加,切削力和切削温度都迅速增加,使得切削条件恶化并加速刀具磨损,从而导致刀具过早失效。将超声椭圆振动加工技术引入到高速铣削中,进行了钛合金高速旋转超声椭圆振动侧铣削试验。从切屑特征以及刀具后刀面磨损两个方面研究了高速超声椭圆振动铣削参数匹配对钛合金加工的影响。首先基于高速超声椭圆振动铣削过程中刀具-工件的运动学特点推导出高速超声椭圆振动铣削加工参数与振动参数间的匹配关系,然后利用本实验室自行研制的超声椭圆振动铣削装置进行了不同参数匹配关系下的验证性切削试验。试验结果表明：合理的参数匹配使得超声椭圆振动铣削在高速条件下依然能够实现分离型断续切削加工。相比普通铣削加工,分离型的高速超声椭圆振动铣削能够获得更加微细的切屑,切削热能够被及时地带走;良好的切削条件使得刀具的后刀面磨损均匀而缓慢,从而延长刀具的使用寿命;高速超声椭圆振动铣削能够有效地提高生产效率。     

The effects of cutting parameters on tool life and wear mechanisms of CBN tool in high-speed face milling of hardened steel

High-speed face milling of AISI H13 hardened steel is conducted in order to investigate the effects of cutting parameters on tool life and wear mechanisms of the cubic boron nitride (CBN) tools. Cutting speeds ranging from 400 to 1,600 m/min are selected. For each cutting speed, the metal removal rate and axial depth of cut are fixed, and different combinations of radial depth of cut and feed per tooth are adopted. The tool life, tool wear progression, and tool wear mechanisms are analyzed for different combinations of cutting parameters. It is found that for most of the selected cutting speeds, the tool life increases with radial depth cut and then decreases. For each cutting speed, the CBN tool life can be enhanced by means of adopting suitable combination of cutting parameters. When the cutting speed increases, the normal wear stage becomes shorter and the tool wear rate grows larger. Because of the variations of cutting force and tool temperature, the tool wear mechanisms change with different combinations of cutting parameters even at the same cutting speed. At relatively low cutting speed, in order to acquire high tool life of the CBN tool, the tool material should possess sufficient capability of resisting adhesion from the workpiece. When relatively high cutting speed is adopted, retention of mechanical properties to high cutting temperature and resistance to mechanical impact are crucial for the enhancement of the CBN tool life.     

大进给铣削沉淀硬化不锈钢刀具失效分析及切削参数优化

针对大进给硬质合金刀具铣削沉淀硬化不锈钢（05Cr17Ni4Cu4Nb）寿命短、效率低的问题,采用单因素法和正交试验法开展刀具磨损试验,并进行回归分析,得到了刀具寿命经验公式。利用有限元仿真方法获得了切削力、刀具切削刃温度和应力场分布情况,结合磨损测量结果及磨损形貌分析了刀具的失效机理。根据有限元仿真结果和刀具寿命经验公式,综合考虑切削效率和刀具磨损,运用等寿命-效率曲面响应法进行切削参数优化,得到了刀具的最佳切削参数及在该切削参数下刀具的寿命。     

硬质合金刀具铣削30CrNi3MoV高强度钢的切削性能研究

30CrNi3MoV高强度钢是某兵器型号专用的难加工材料。本文在分析材料铣削特性的基础上,选择了合理的铣刀盘和铣刀片的几何参数,通过刀具磨损与耐用度对比试验优选出了最佳的硬质合金刀具牌号,并给出了铣削过程中硬质合金铣刀片的典型磨破损形态。研究结果表明:添加钽、铌的硬质合金是解决30CrNi3MoV高强度钢铣削工艺理想的刀具材料,在92m/min~186m/min的铣削速度范围内,刀具耐用度可达10min~49min;由于材料切削温度高和机械冲击严重,铣刀片的磨破损形态主要表现为后刀面上狭长的热磨损带,倒棱上长方形的磨损坑,前刀面上扇形剥落和刀尖处三角形崩碎破损等。     

高速铣削近α钛合金的切削温度研究

切削温度不仅直接影响刀具的磨损和耐用度,而且也影响工件的加工精度和已加工表面质量。由于钛合金导热性差和化学亲和性强等原因,通常在其切削加工时切削温度高、刀具磨损严重,致使切削速度难以进一步提高。本文重点对钛合金高速铣削时的切削温度进行试验研究,阐明夹丝半人工热电偶法测温原理和所测热电势信号的物理意义。试验选用了3种不同类型的硬质合金刀具,系统地研究了切削用量、冷却条件及刀具磨损等因素对近α钛合金高速铣削时切削温度的影响。     

高温合金GH4169高效插铣工艺试验研究

针对高温合金GH4169插铣粗加工工艺,通过单因素试验,从切削力及刀具磨损两方面评价顺、逆插铣加工方式,并根据优选出的顺插加工方式,分别研究插铣行距及每齿进给量对切削力、刀具寿命及刀具寿命内材料去除总量的影响规律,从而优选出合适的行距及进给。结果表明,在试验研究工艺条件下,当ae=5.0mm,fz=0.017mm/z时,切削力较小,刀具寿命较长,刀具寿命内的材料去除总量较大,且效率较高。     

硬质合金刀具高速车铣和铣削TC4钛合金磨损试验对比

采用H13A未涂层硬质合金刀具对TC4钛合金进行高速正交车铣和铣削试验,并从刀具磨损破损形态、磨损机理及其寿命等方面进行对比分析。研究表明:高速正交车铣和铣削钛合金时,前、后刀面主要以粘结磨损为主,车铣加工时在切削刃口易形成积屑瘤及连续切屑,但对刀具材料粘结较轻;高速铣削时,对刀具材料粘接较重,在前刀面刃口附近形成凹坑及崩刃;后刀面最大磨损的位置不相同。试验对比了相同切削条件时刀具使用寿命,结果表明采用正交车铣加工可以获得更长的刀具使用寿命。     

A new tool wear estimation method based on shape mapping in the milling process

In the milling process, tool wear has a great influence on product machining quality, especially for a difficult-to-cut material. In this paper, a new approach based on shape mapping is proposed to acquire tool wear in order to establish an off-line tool wear predicting model for assessing the degree of wear and remaining useful life. The new approach maps tool wear shape into a metal material by milling holes mode after finishing each of the machining experiments. The metal material has low influence on tool wear compared to the experimental material. Thus, a series of mapped holes, which can represent the worn tool information, are formed on the metal material when finishing all milling experiments. These mapped holes on the metal material are analyzed according to all types of milling cutters in order to establish the relationship between the characteristic parameters of these mapped holes and tool wear. According to the established relationship, the characteristic parameters of these mapped holes are measured on the coordinate measure machine. The tool wear of each machining experiment can be obtained from the measured characteristic parameters of these mapped holes. The new tool wear estimation method does not require the stoppage of the machine tool and the removal of the cutter to measure tool wear in the process of conducting tool wear experiments. The new method can increase the machine tool efficiency of tool wear machining experiments and provide an efficient way to acquire tool wear in the process of establishing an off-line tool wear predicting model. In order to verify the new tool wear estimation method, a series of machining experiments were conducted on the five-axis machining center for cemented carbide cutting tool milling stainless steel. Experiments show that the shape mapping strategy of tool wear can allow for an effective assessment of tool wear and indicate good correlation with the expected wear characteristics and easily conduct tool wear experiments.     

氧化锆生物陶瓷铣削的刀具磨损

为了研究完全烧结氧化锆陶瓷铣削过程中金刚石刀具的磨损及其对切削过程的影响,进行了氧化锆铣削实验。分析了刀具磨损带的扩展过程以及切削力随刀具磨损过程的变化规律。通过观测切削表面微观形貌随刀具磨损过程的演变,对刀具磨损与切削模式之间的关系进行了探讨,最后揭示了刀具磨损机理。研究结果表明：铣削氧化锆陶瓷时刀具磨损随切削过程从刃口扩展到后刀面,同时切削模式从延脆混合去除转变为完全脆性去除,刀具磨损模式是崩刃、剥落及石墨化磨损。     

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.     

Effects of Cutting Parameters on Tool Insert Wear in End Milling of Titanium Alloy Ti6A14V

Titanium alloy is a kind of typical hard-to-cut material due to its low thermal conductivity and high strength at elevated temperatures, this contributes to the fast tool wear in the milling of titanium alloys. The influence of cutting conditions on tool wear has been focused on the turning process, and their influence on tool wear in milling process as well as the influence of tool wear on cutting force coefficients has not been investigated comprehensively. To fully understand the tool wear behavior in milling process with inserts, the influence of cutting parameters on tool wear in the milling of titanium alloys Ti6Al4 V by using indexable cutters is investigated. The tool wear rate and trends under different feed per tooth, cutting speed, axial depth of cut and radial depth of cut are analyzed. The results show that the feed rate per tooth and the radial depth of cut have a large influence on tool wear in milling Ti6Al4 V with coated insert. To reduce tool wear, cutting parameters for coated inserts under experimental cutting conditions are set as: feed rate per tooth less than 0.07 mm, radial depth of cut less than 1.0 mm, and cutting speed sets between 60 and 150 m/min. Investigation on the relationship between tool wear and cutting force coefficients shows that tangential edge constant increases with tool wear and cutter edge chipping can lead to a great variety of tangential cutting force coefficient. The proposed research provides the basic data for evaluating the machinability of milling Ti6Al4 V alloy with coated inserts, and the recommend cutting parameters can be immediately applied in practical production.     

Effects of cutting parameters on tool insert wear in end milling of titanium alloy Ti6Al4V

Titanium alloy is a kind of typical hard-to-cut material due to its low thermal conductivity and high strength at elevated temperatures, this contributes to the fast tool wear in the milling of titanium alloys. The influence of cutting conditions on tool wear has been focused on the turning process, and their influence on tool wear in milling process as well as the influence of tool wear on cutting force coefficients has not been investigated comprehensively. To fully understand the tool wear behavior in milling process with inserts, the influence of cutting parameters on tool wear in the milling of titanium alloys Ti6Al4V by using indexable cutters is investigated. The tool wear rate and trends under different feed per tooth, cutting speed, axial depth of cut and radial depth of cut are analyzed. The results show that the feed rate per tooth and the radial depth of cut have a large influence on tool wear in milling Ti6Al4V with coated insert. To reduce tool wear, cutting parameters for coated inserts under experimental cutting conditions are set as: feed rate per tooth less than 0.07 mm, radial depth of cut less than 1.0 mm, and cutting speed sets between 60 and 150 m/min. Investigation on the relationship between tool wear and cutting force coefficients shows that tangential edge constant increases with tool wear and cutter edge chipping can lead to a great variety of tangential cutting force coefficient. The proposed research provides the basic data for evaluating the machinability of milling Ti6Al4V alloy with coated inserts, and the recommend cutting parameters can be immediately applied in practical production.     

钛合金铣削过程刀具前刀面磨损解析建模

钛合金Ti6Al4V作为典型的航空航天难加工材料,在其铣削过程中硬质合金刀具的磨损会降低加工过程稳定性,进而影响加工效率和已加工表面表面质量。刀具前刀面磨损会导致刀具刃口强度降低,并影响切屑的流向和折断情况。针对前刀面磨损机理进行分析并构建了月牙洼磨损深度预测模型。首先运用解析方法构建了前刀面应力场模型,得到切屑在前刀面滑动过程中的刀具前刀面应力分布情况及磨损位置。基于刀-屑接触关系的基础上建立了前刀面温度场模型。然后,基于所得刀具前刀面应力与温度分布,构建综合考虑磨粒磨损、粘结磨损与扩散磨损的铣刀月牙洼磨损深度预测模型,获得月牙洼磨损预测曲线;结合铣刀月牙洼磨损带沿切削刃方向分布的特点,建立了随时间变化的铣刀前刀面磨损体积预测模型。最后通过试验验证了切削宽度对前刀面磨损的影响规律,预测结果与试验测量值具有较好的吻合性。结果表明随着切削宽度的增加,月牙洼磨损深度及前刀面磨损体积都随之增加。研究结果为钛合金铣削用刀具的设计和切削参数的合理选择提供了理论基础。     

液氮冷却下大进给铣削TC4钛合金的试验研究

钛合金是现代飞行器的主要结构材料之一,是一种典型的难加工材料。针对切削加工钛合金时刀具磨损快、表面质量不易控制等难题,将TC4钛合金作为研究对象,以液氮作为冷却介质,进行了TC4钛合金的大进给铣削试验,测试了液氮冷却条件下大进给铣削TC4钛合金的铣削力、铣削温度以及刀具磨损等,并与乳化液和低温冷风条件下的测试结果进行了对比分析。结果表明:在以较大的切削速度和每齿进给量铣削TC4钛合金时,采用液氮冷却比使用乳化液能更有效地降低切削力和切削温度;比采用低温冷风冷却能更有效地延长刀具寿命。     

GH4169插铣参数对刀具寿命影响规律及磨损形貌研究

为了研究GH4169插铣加工中切削参数对刀具寿命的影响规律,采用正交试验法,使用整体硬质合金刀具进行GH4169的插铣试验。运用多元线性回归分析的方法建立刀具寿命的经验公式,分析了切削参数对刀具寿命的影响规律;并采用电子扫描显微镜(SEM)对刀具在不同阶段的磨损形貌进行观测。结果表明:在插铣加工高温合金GH4169过程中,铣削速度对刀具寿命的影响最大,其次是每齿进给量和径向切深。     

Cutting performance of coated carbide tools in high-speed face milling of AISI H13 hardened steel

In the present study, high-speed face milling of AISI H13 hardened steel was conducted to investigate the cutting performance of coated carbide tools. The characteristics of chip morphology, tool life, tool wear mechanisms, and surface roughness were analyzed and compared for different cutting conditions. It was found that as the cutting speed increased, the chip morphology evolved in different ways under different milling conditions (up, down, and symmetric milling). Individual saw-tooth segments and sphere-like chip formed at the cutting speed of 2,500 m/min. Owing to the relatively low mechanical load, longest tool life can be obtained in up milling when the cutting speed was no more than 1,000 m/min. As the cutting speed increased over 1,500 m/min, highest tool life existed in symmetric milling. When the cutting speed was 500 m/min, owing to the higher mechanical load, the flaked region on the tool rake face in symmetric milling was much larger than that in up and down milling. There was no obvious wear on the tool rake face at the cutting speed of 2,500 m/min due to the short tool-chip contact length. In symmetric milling, the delamination of tool material, which did not occur in up and down milling, was caused by the relatively large cutting force. Abrasion had great effect on the tool flank wear in symmetric milling. With the increment of cutting speed, surface roughness decreased first and then increased rapidly. Lowest surface roughness can be obtained at the cutting speed of about 1,500 m/min.     

低温喷雾射流铣削Ti40阻燃钛合金的刀具耐用度

为研究低温喷雾射流对铣削Ti40阻燃钛合金过程中刀具磨损的改善效果,通过油冷浇注以及低温喷雾射流冷却润滑方式的对比分析,探讨了铣削过程中涂层硬质合金刀具的磨损行为与耐用度。研究了低温喷雾射流加工过程中气体压力、液体压力、靶距、液体流量对铣削温度的影响,利用响应曲面法建立了刀具铣削温度数学模型,确定了喷雾射流参数的最佳值,并进行了铣削验证。结果表明：低温喷雾射流较油冷浇注冷却润滑方式可更有效地抑制刀具磨损,能够成倍地提高刀具耐用度;建立的刀具铣削温度模型有效度高,误差较小,通过优化低温喷雾射流参数有效提高了刀具耐用度;低温喷雾射流铣削Ti40阻燃钛合金的最佳参数值为：气体压力0.5MPa,液体压力0.5MPa,靶距5mm,液体流量83mL/min。     

平面铣削刀具前刀面瞬态切削温度的研究

刀具切削温度对刀具寿命、刀具磨损等有重要影响。因此在实际加工之前预测出刀具温度,对合理选择切削参数、优化数控程序等均具有重要意义。平面铣削等断续切削过程的热条件不同于车削等连续切削过程。用数学物理方法建立了平面铣削过程刀具的一维传热学模型,用解析的方法预测平面铣削过程中刀具前刀面的温度分布,考虑了刀具切出时空气强化对流散热对刀具前刀面温度的影响。结果表明,刀具切入时间和切出时间对刀具温度有较大影响。用文献中断续车削刀具温度实验数据对铣削刀具前刀面温度的传热学预测模型进行了验证,结果表明二者趋势一致,但平面铣削预测的刀具温度略低于断续车削的刀具温度。     

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。     

Detection process approach of tool wear in high speed milling

The cutting tool wear degrades the quality of the product in the manufacturing process, for this reason an on-line monitoring of the cutting tool wear level is very necessary to prevent any deterioration. Unfortunately there is no direct manner to measure the cutting tool wear on-line. Consequently we must adopt an indirect method where wear will be estimated from the measurement of one or more physical parameters appearing during the machining process such as the cutting force, the vibrations, or the acoustic emission, etc. The main objective of this work is to establish a relationship between the acquired signals variation and the tool wear in high speed milling process; so an experimental setup was carried out using a horizontal high speed milling machine. Thus, the cutting forces were measured by means of a dynamometer whereas; the tool wear was measured in an off-line manner using a binocular microscope. Furthermore, we analysed cutting force signatures during milling operation throughout the tool life. This analysis was based on both temporal and frequential signal processing techniques in order to extract the relevant indicators of cutting tool state. Our results have shown that the variation of the variance and the first harmonic amplitudes were linked to the flank wear evolution. These parameters show the best behavior of the tool wear state while providing relevant information of this later.