PCD刀具微细铣削硬质合金刀具磨损研究

使用PCD刀具进行微细铣削硬质合金的刀具磨损试验,研究了PCD微细铣刀的磨损形态和磨损机理。结果表明,PCD微细铣刀的磨损主要集中在刀尖和底刃上,造成刀具磨损的原因主要包括粘结磨损、磨料磨损以及微崩刃。刀具磨损导致硬质合金加工表面粗糙度逐渐增大。     

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。     

切削速度对轴向车铣TC4钛合金刀具磨损的影响

为研究高速轴向车铣TC4钛合金时硬质合金刀具的磨损特性,选择S30T硬质合金刀片分别在100m/min、150m/min和200m/min三种切削速度下对TC4进行了轴向车铣试验,分析了不同切削速度对刀具使用性能的影响。研究结果表明:高速轴向车铣TC4钛合金外圆时刀具磨损主要发生在刀片的刀尖刃口及后刀面;磨损形式以粘结磨损为主;刀具的磨损速度随着速度的增加而增大;S30T刀片在100m/min的切削速度下具有较好的刀具耐用度,在150m/min、200m/min的切削速度刀具磨损较快,不适于实际切削加工。     

PCD刀具切削颗粒增强铝基复合材料时刀具磨损研究

通过高颗粒含量铝基复合材料切削加工时PCD刀具的磨损试验,研究了切削该种材料时PCD刀具的磨损形态及磨损机理。刀具磨损区微观形貌的检测分析结果表明,PCD刀具的磨损形态主要表现为前刀面磨损和后刀面磨损,造成刀具磨损的主要原因是磨料磨损和粘结磨损。采用超声波振动切削技术可减小刀具磨损。     

铝合金薄壁中空结构件重负荷铣削刀具寿命及刀具磨损研究

使用高速钢和硬质合金刀具,在机床转速n=2000-5000r/min、进给速度vf=1000mm/min、轴向切深ap=20mm、径向切宽aw=10-20mm的切削用量范围内对铝合金薄壁中空结构件重负荷铣削加工刀具寿命及刀具磨损进行研究。结果表明:M42高速钢刀具由于刀具磨损率高、刀具破损和粘结严重而不适合该结构件的重负荷铣削;非波刃粉末冶金高速钢和硬质合金刀具具有良好的适应性,但无刀尖圆弧半径的高速钢刀具易发生刀尖破损,涂层硬质合金刀具易发生涂层过早剥落;波刃粉末冶金高速钢刀具易于发生刀具严重粘结,只宜在较低的机床转速下进行重负荷铣削加工;机床转速和径向切宽对刀具寿命有显著影响。     

PCD和硬质合金刀具车削钛基复合材料时刀具磨损特征研究

以原位生成晶须和颗粒混合增强钛基复合材料为车削对象,在切削速度为60~120m/min的条件下,对聚晶金刚石（PCD）和硬质合金刀具开展了车削性能试验研究。研究表明,PCD刀具的切削力为硬质合金刀具的77%～88%,其切削温度为硬质合金刀具的65%～82%。无论是高速切削,还是低速切削,PCD刀具都经历初期剧烈磨损而后稳定磨损的过程,而硬质合金刀具仅有急剧磨损的过程。刀具磨损特征方面,PCD刀具主要发生磨粒磨损和黏结磨损,硬质合金刀具主要发生月牙洼磨损、黏结磨损和扩散磨损。     

高速铣削AISI 4340合金结构钢时涂层刀具磨损机理研究

针对AISI 4340合金结构钢难加工的特点,选用PVD硬质合金涂层刀具进行高速干铣削试验,选用扫描电子显微镜(SEM)观察失效刀具表面的磨损形貌特征,选用能谱分析仪(EDS)分析磨损刀具表面的元素分布及含量,揭示刀具的磨损机理。研究结果表明:刀具寿命与切削参数选取有关,随着切削速度的增加,刀具磨损加快,刀具寿命降低。硬质合金涂层刀具的主要磨损形式是前刀面磨损和后刀面磨损,前刀面磨损机理主要是粘结磨损、涂层剥落、切削刃微崩刃;后刀面磨损机理主要是磨粒磨损、粘结磨损、扩散磨损、微裂纹。     

高速铣削Ti-10V-2Fe-3Al的刀具磨损试验研究

针对切削加工Ti-10V-2Fe-3Al钛合金时刀具磨损迅速、加工效率低的问题,开展硬质合金刀具高速铣削Ti-10V-2Fe-3Al的刀具寿命试验,以研究刀具的磨损机理,分析刀面磨损的发展以及对切削力的影响。利用扫描电子显微镜观察了后刀面磨损区域的微观形貌并对元素成分进行了能谱分析。实验结果表明：高速铣削Ti-10V-2Fe-3Al时硬质合金刀具的磨损形式为后刀面带状磨损与局部崩刃,伴有明显的切屑黏附与热裂纹;磨损区域有工件材料的元素向硬质合金内扩散的迹象出现;切屑流的黏附与撕扯导致硬质合金的颗粒脱落,切削刃逐步退化为洼形区域,其与后刀面交界的棱边代替原切削刃进行切削直至剥落。     

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。     

硬质合金刀具高速车削钛合金的切削性能研究

采用单因素试验法,用未涂层硬质合金刀具和TiAlN涂层硬质合金刀具对Ti-6Al-4V钛合金进行了高速干车削试验,通过对切削过程中切削力、刀具寿命、切削温度以及加工表面粗糙度的分析,得出了两种刀具高速干车削钛合金的切削性能,为钛合金高速切削刀具的设计提供了试验依据。     

The effect of cutting parameters and cutting tools on machining performance of carbon graphite material

Abstract

The present study focuses on the effects of cutting speed, feed rate and cutting tool material on the machining performance of carbon graphite material. Polycrystalline Diamond (PCD) cutting tools are used in machining experiments and its performance is compared with the tungsten carbide (WC) and Cubic Boron Nitride (CBN) tools. Machining performance criteria such as flank and nose wear and resulting surface topography and roughness of machined parts were studied. This study illustrates that feed rate and cutting tool material play a dominant role in the progressive wear of the cutting tool. The highest feed rate and cutting speed profoundly reduce the tool wear progression. The surface roughness and topography of specimens are remarkably influenced from the tool wear. Major differences are found in the wear mechanisms of PCD and WC and CBN cutting tools.     

A study of the cutting-induced heating effect on the machined surface in ultra-precision raster milling of 6061 Al alloy

Ti-6Al-4V alloy is an attractive material in many industries due to its unique and excellent combination of strength to weight ratio and their resistance to corrosion. However, because of its low thermal conductivity and high chemical reactivity, Ti-6Al-4V alloy is generally classified as a difficult-to-cut material that can be characterized by low productivity and rapid tool wear rate even at conventional cutting speeds. It is well known that tool wear has a strong relationship with the cutting forces and a sound knowledge about correlation between cutting forces variation and tool wear propagation is vital to monitor and optimize the automatic manufacturing process. In the present study, high-speed end-milling of Ti-6Al-4V alloy with uncoated cemented tungsten carbide tools under dry cutting conditions is experimentally investigated. The main objective of this work is to analyze the tool wear and the cutting forces variation during high-speed end-milling Ti-6Al-4V alloy. The experimental results show that the major tool wear mechanisms in high-speed end-milling Ti-6Al-4V alloy with uncoated cemented tungsten carbide tools are adhesion and diffusion at the crater wear along with adhesion and abrasion at the flank wear. The cutting force component in the negative y-direction is more dominant of the three components and displays significantly higher magnitudes than that of the other two components in x- and z-directions. The variation of cutting force component F _y has a positive correlation with the tool wear propagation, which can be used as a tool wear indicator during automatic manufacturing process.     

The performance of PCD tools in high-speed milling of Ti6Al4V

Tool performance of conventional tools is poor and a major constraint when used in milling titanium alloys at elevated cutting speeds. At these high cutting speeds, the chemical and mechanical properties of Ti6Al4V cause complex wear mechanisms. In this paper, a fine-grain polycrystalline diamond (PCD) end mill tool was tested, and its wear behavior was studied. The performance of the PCD tool has been investigated in terms of tool life, cutting forces, and surface roughness. The PCD tool yielded longer tool life than a coated carbide tool at cutting speeds above 100?m/min. A slower wear progression was found with an increase in cutting speeds, whereas the norm is an exponential increase in tool wear at elevated speeds. Observations based on scanning electron microscope (SEM) and energy dispersive spectroscopy (EDAX) analysis suggest that adhesion of the workpiece is the wear main type, after which degradation of the tools accelerates probable due to the combined effect of high temperature degradation coupled with abrasion.     

Effect of machining parameters on surface roughness and tool wear for 7075 Al alloy SiC composite

In the present study, an attempt has been made to investigate the influence of cutting speed, depth of cut, and feed rate on surface roughness during machining of 7075 Al alloy and 10 wt.% SiC particulate metal-matrix composites. The experiments were conducted on a CNC Turning Machine using tungsten carbide and polycrystalline diamond (PCD) inserts. Surface roughness of 7075Al alloy with 10 wt.% SiC composite during machining by tungsten carbide tool was found to be lower in the feed range of 0.1 to 0.3 mm/rev and depth of cut (DOC) range of 0.5 to 1.5 mm as compared to surface roughness at other process parameters considered. Above cutting speed of 220 m/min surface roughness of SiC composite during machining by PCD tool was less as compared to surface roughness at other values of cutting speed considered. Wear of tungsten carbide and PCD inserts was analyzed using a metallurgical microscope and scanning electron microscope. Flanks wear of carbide tool increased by a factor of 2.4 with the increase of cutting speed from 180 to 240 m/min at a feed of 0.1 mm/rev and a DOC of 0.5 mm. On the other hand, flanks wear of PCD insert increased by only a factor of 1.3 with the increase of cutting speed from 180 to 240 m/min at feed of 0.1 mm/rev and DOC 0.5 mm.     

Micro cutting of tungsten carbides with sem direct observation method

This paper describes the micro cutting of wear resistant tungsten carbides using PCD (Poly-Crystalline Diamond) cutting tools in performance with SEM (Scanning Electron Microscope) direct observation method. Turning experiments were also carried out on this alloy (V50) using a PCD cutting tool. One of the purposes of this study is to describe clearly the cutting mechanism of tungsten carbides and the behavior of WC particles in the deformation zone in orthogonal micro cutting. Other purposes are to achieve a systematic understanding of machining characteristics and the effects of machining parameters on cutting force, machined surface and tool wear rates by the outer turning of this alloy carried out using the PCD cutting tool during these various cutting conditions. A summary of the results are as follows : (1) From the SEM direct observation in cutting the tungsten carbide, WC particles are broken and come into contact with the tool edge directly. This causes tool wear in which portions scrape the tool in a strong manner. (2) There are two chip formation types. One is where the shear angle is comparatively small and the crack of the shear plane becomes wide. The other is a type where the shear angle is above 45 degrees and the crack of the shear plane does not widen. These differences are caused by the stress condition which gives rise to the friction at the shear plane. (3) The thrust cutting forces tend to increase more rapidly than the principal forces, as the depth of cut and the cutting speed are increased preferably in the orthogonal micro cutting. (4) The tool wear on the flank face was larger than that on the rake face in the orthogonal micro cutting. (5) Three components of cutting force in the conventional turning experiments were different in balance from ordinary cutting such as the cutting of steel or cast iron. Those expressed a large value of thrust force, principal force, and feed force. (6) From the viewpoint of high efficient cutting found within this research, a proper cutting speed was 15 m/min and a proper feed rate was 0.1 mm/rev. In this case, it was found that the tool life of a PCD tool was limited to a distance of approximately 230 m. (7) When the depth of cut was 0.1 mm, there was no influence of the feed rate on the feed force. The feed force tended to decrease, as the cutting distance was long, because the tool was worn and the tool edge retreated. (8) The main tool wear of a PCD tool in this research was due to the flank wear within the maximum value of V_max being about 260 μ.     

硬质合金刀具铣削Ti6Al4V时刀具磨损及切削力研究

对硬质合金刀具在干切削状态下铣削Ti6Al4V磨损机理和切削力进行了试验研究,切削速度分别为40、80、120、160m／min。分析了切削力与切削方式、切削速度、切削路程的关系。最后,对刀具的磨损形态和磨损机理进行了探讨。结果表明粘结、扩散是硬质合金铣刀的主要磨损机理。     

Failure mechanisms of a PCD tool in high-speed face milling of Ti–6Al–4V alloy

High-speed milling tests were carried out on Ti–6Al–4V titanium alloy with a polycrystalline diamond (PCD) tool. Tool wear morphologies were observed and examined with a digital microscope. The main tool failure mechanisms were discussed and analyzed utilizing scanning electron microscope, and the element distribution of the failed tool surface was detected using energy dispersive spectroscopy. Results showed that tool flank wear rate increased with the increase in cutting speed. The PCD tool is suitable for machining of Ti–6Al–4V titanium alloy with a cutting speed around 250 m/min. The PCD tool exhibited relatively serious chipping and spalling at cutting speed higher than 375 m/min, within further increasing of the cutting speed the flank wear and breakage increased greatly as a result of the enhanced thermal–mechanical impacts. In addition, the PCD tool could hardly work at cutting speed of 1,000 m/min due to the catastrophic fracture of the cutting edge and intense flank wear. There was evidence of workpiece material adhesion on the tool rake face and flank face in very close proximity to the cutting edge rather than on the chipped or flaked surface, which thereby leads to the accelerating flank wear. The failure mechanisms of PCD tool in high-speed wet milling of Ti–6Al–4V titanium alloy were mainly premature breakage and synergistic interaction among adhesive wear and abrasive wear.     

Study on finish-turning of NiCr20TiAl nickel-based alloy using Al2O3/TiN-coated carbide tools

Al₂O₃/TiN-coated tungsten carbide tools were used for finish-turning of NiCr20TiAl nickel-based alloy under various cutting conditions. The cutting forces, surface integrity, and tool wear were investigated, and their formation mechanisms were discussed. The inter-diffusing and transferring of elements between Al₂O₃/TiN-coated tungsten carbide tool and NiCr20TiAl nickel-based alloy were studied during machining. The plastic flow of NiCr20TiAl alloy was present on the machined surface by the lower cutting forces. The flaking of coating and matrix of tools and the heavier plucking and cavities of the machined surface were induced by the higher cutting forces at higher cutting parameters. The tensile residual stress was engendered on the machined surface and increased with the cutting parameters. In view of surface quality and tool wear, the cutting speed of 60?min and feed of 0.15?mm/r are recommended, and depth of cut should not exceed 0.4?mm when Al₂O₃/TiN-coated carbide tools are used for the finish-turning of the NiCr20TiAl alloy.     

高速切削刀具磨损寿命的研究

分析了高速切削时刀具的磨损形态 ,综述了各种高速切削刀具材料 (包括陶瓷刀具、立方氮化硼刀具、金刚石刀具、金属陶瓷刀具和涂层刀具 )高速切削时的磨损机理 ,讨论了高速切削铸铁、淬硬钢和镍基合金时刀具的磨损寿命。