金刚石涂层刀具铣削高硅铝合金的性能研究

选用未涂层、TiAlN涂层及金刚石涂层整体硬质合金两刃平头立铣刀,在相同切削参数下进行高硅铝合金的高速铣削加工试验。试验结果表明:金刚石涂层铣刀具有良好的耐磨性,在切削过程中刀刃磨损均匀缓慢,刀具使用寿命长,加工表面粗糙度值稳定性好,是铣削高硅铝合金的理想刀具。     

两种铣刀在切削碳纤维增强塑料时的磨损机理

用TiB2涂层硬质合金铣刀和金刚石涂层硬质合金铣刀分别对碳纤维增强塑料进行铣削加工试验,通过扫描电镜、三维视频显微镜等研究了两种涂层刀具的磨损形态和磨损机理。结果表明:刀具交替切削软的树脂基体和高强度的碳纤维而产生的交变应力以及高强度碳纤维对切削刃的高频冲击作用是促使刀具发生崩刃和涂层剥落的主要原因;金刚石涂层刀具由于有极高的硬度和耐磨性,其使用寿命明显高于TiB2涂层刀具,且加工表面的粗糙度低于TiB2涂层刀具的;两种刀具铣削碳纤维增强塑料的磨损机理均为磨料磨损。     

金刚石涂层铣刀铣削高硅铝合金CE11的刀具磨损分析

在国内外对高硅铝合金切削摩擦磨损特性的研究基础上,以正交试验法为基础,利用有限元仿真软件DEFORM-3D对金刚石涂层铣刀铣削高硅铝合金CE11过程进行虚拟仿真分析,并研究铣削用量的改变对刀具磨损的影响规律。基于仿真试验结果,对金刚石涂层刀具铣削高硅铝合金的铣刀磨损量试验数据进行极差分析,优选出最小磨损量的最佳切削用量方案,并通过试验验证了仿真结果的正确性。     

铣削玻璃纤维/碳纤维芳纶纸蜂窝板实验研究

以玻璃纤维/碳纤维芳纶纸蜂窝板铣削试验为基础,研究了3种不同刀具和不同铣削宽度对刀具磨损和工件加工质量的影响。结果表明:随着铣削宽度的增加,刀具磨损都随之增加。其中,硬质合金铣刀磨损最严重,磨损量远大于金刚石涂层刀具。在切削参数相同的条件下,硬质合金铣刀的切削效果最差,而人字形和菱齿CVD金刚石薄膜涂层铣刀的切削效果明显改善,前者玻璃纤维的切削效果最好,后者碳纤维的切削效果最佳。     

TiAlN涂层铣刀铣削CE11高硅铝合金的刀具磨损分析

在分析高硅铝合金切削摩擦磨损特性的国内外研究现状基础上,以正交试验法为基础,利用DEFORM 3D有限元仿真软件对TiAlN涂层铣刀铣削CE11高硅铝合金的铣削过程进行虚拟仿真分析,研究铣削用量的改变对刀具磨损的影响规律。基于仿真试验结果,对TiAlN涂层刀具铣削高硅铝合金的铣刀磨损量试验数据进行极差分析,优选出最小磨损量的最佳切削用量方案,并通过试验验证仿真结果的正确性。     

含Si涂层刀具铣削复合铝2024的性能研究

选用含Si涂层、TiAlN涂层和未涂层的整体硬质合金四刃平底立铣刀,在相同的切削参数下进行复合铝2024的铣削加工试验。试验结果表明:含Si涂层铣刀具有良好的耐磨性,在切削过程中刀刃磨损均匀缓慢,刀具使用寿命长,加工表面光洁度好,是铣削复合铝2024的理想刀具。     

TiAlN涂层硬质合金刀具铣削35CrMoSiV钢的切削性能研究

采用有和无PVD TiAlN涂层的细晶硬质合金铣刀对35CrMoSiV合金钢进行了干式端面铣削试验。分别测量了有、无涂层情况下铣刀后刀面径向磨损量和加工槽的表面粗糙度,通过光学显微镜观察了切屑,利用扫描电子显微镜(SEM)和电子能谱(EDX)分析了后刀面的磨损形态。研究结果表明:TiAlN涂层明显提高了硬质合金刀具的切削性能;硬质合金刀具后刀面磨损机制主要为粘着磨损和磨粒磨损,而涂层损伤是粘着磨损、剥层和氧化磨损共同作用的结果;在正常工作区内,提高铣削的转速和进给量,有利于减轻刀具的粘着,提高切削效率和质量。     

铣削碳纤维复合材料刀具磨损试验研究

采用未涂层和CVD金刚石薄膜涂层两种硬质合金铣刀,对碳纤维复合材料进行铣削试验,使用3D激光扫描镜对刀具磨损形貌和磨损量进行测量,分析了刀具的磨损机理和切削用量对刀具磨损的影响。试验结果表明：后刀面磨损是两种刀具的主要磨损形式,磨损机理为磨料磨损,未涂层硬质合金铣刀同时存在着刀具破损现象;切削速率和背吃刀量对刀具后刀面的磨损影响较为显著;未涂层与CVD金刚石薄膜涂层硬质合金铣刀相比较,后刀面的磨损量保持在2．3—3．8倍之间,从刀具的耐磨性考虑,CVD金刚石薄膜涂层硬质合金铣刀可以用于碳纤维复合材料的生产加工。     

切削模具钢的专用高效刀具涂层——火凤凰涂层

高硬度模具钢(硬度HRC60～65),性能优良、延伸率小、塑性低,易于形成高光洁加工表面.但是对其进行铣削加工时存在着由于切削温度和切削力过高引起的诸多问题,如较差的表面质量以及较低的刀具寿命等.上海工具厂有限公司开发了高效涂层系列-火凤凰涂层.相对于无涂层刀具以及常规TiAlN涂层刀具,火凤凰涂层铣刀在加工质量和刀具耐用度方面有着突出的表现.本文通过对火凤凰涂层铣刀切削加工性能进行评价,从刀具失效机理、磨损过程、切削力、切屑变形系数以及已加工表面质量等全方位进行研究,对实现高硬度模具钢的高效率.高精度刀具应用和推广提供了重要的应用理论依据.     

新型F92铁素体耐热钢的铣削加工性能

对难加工材料F92耐热钢进行了铣削试验,在干切削条件下使用硬质合金涂层立铣刀进行加工,分析了该材料的铣削机理,研究了切削速度、进给量、切削深度三因素对切削力、加工表面粗糙度以及刀具磨损的影响,在此基础上获得了高效率、高精度的加工工艺参数.结果表明:当切削速度为94 m·min-1、每齿进给量为0.06 mm、切削深度为7.5 mm时主切削力较小(<170 N),同时可以得到较好的表面加工质量(Ra<0.4μm),铣刀的主要的磨损形式是涂层剥落和磨粒磨损.     

Investigation of cutting forces,surface integrity,and tool wear when high-speed milling of high-volume fraction SiC<Subscript>p</Subscript>/Al6063 composites in PCD tooling

This paper focused on high-speed milling of Al6063 matrix composites reinforced with high-volume fraction of small-sized SiC particulates and provided systematic experimental study about cutting forces, thin-walled part deformation, surface integrity, and tool wear during high-speed end milling of 65% volume fraction SiC_p/Al6063 (Al6063/SiC_p/65p) composites in polycrystalline diamond (PCD) tooling. The machined surface morphologies reveal that the cutting mechanism of SiC particulates plays an important role in defect formation mechanisms on the machined surface. In high-speed end milling of Al6063/SiC_p/65p composites, the cutting forces are influenced most considerably by axial depth of cut, and thus the axial depth of cut plays a dominant role in the thin-walled parts deformation. Increased milling speed within a certain range contributes to reducing surface roughness. The surface and sub-surface machined using high-speed milling suffered from less damage compared to low-speed milling. The milling speed influence on surface residual stress is associated with milling-induced heat and deformation. Micro-chipping, abrasive wear, graphitization, grain breaking off, and built-up edge are the dominated wear mechanism of PCD tools. Finally, a series of comparative experiments were performed to study the influence of tool nose radius, average diamond grain size, and machining parameters on PCD tool life.     

Elliptical vibration cutting of hardened die steel with coated carbide tools

Elliptical vibration cutting of hardened die steel with coated carbide tools is examined in this research in order to achieve low-cost high-precision machining. Diamond coated tools are applied because of superior hardness of their polycrystalline diamond coating and its low manufacturing cost. TiN coated tools are also tested, since they are widely used for conventional machining of steels. Machinability of hardened die steel by the elliptical vibration cutting with coated carbide tools is discussed in three aspects in this study, i.e. transferability of cutting edge profile to cut surface, cutting force, and tool life. The transferability is evaluated quantitatively by calculating correlation coefficients of measured roughness profiles. It is clarified that the diamond coated tools have high transferability which leads to diffraction of light on the surface machined at micro-scale pick feed. Total cutting forces including ploughing components are measured at various feed rates, and then shearing components and ploughing components are separated utilizing linear regression. The measured results indicate, for example, that the all forces become considerably smaller only when elliptical vibration is applied to the TiN coated tool without cutting fluid. It is also found that this considerable reduction of forces interestingly corresponds to higher friction coefficient, which is identified from the ploughing components. Tool life tests are carried out by various machining methods, i.e. elliptical vibration/ordinary wet/dry cutting with diamond/TiN coated tools. The result shows, for example, that the flank wear is smallest in the wet elliptical vibration cutting with the diamond coated tool.     

涂层Si_3N_4陶瓷刀具切削性能研究

研究了不同切削参数对TiN+Al2O3涂层氮化硅陶瓷刀具切削灰铸铁的切削性能的影响,使用工具显微镜、SEM/EDS手段分析了涂层氮化硅刀具的磨损机理,实验还采用相同基体氮化硅陶瓷刀具做了对比分析。研究结果显示TiN+Al2O3涂层氮化硅刀具可以承受比较大的切削用量,对提高加工效率有重大意义;还发现涂层氮化硅陶瓷刀具主要失效形式为磨粒磨损,粘结磨损,在较高切削速度条件下前刀面还会出现因化学磨损形成的月牙洼。     

EFFECT OF CUTTING SPEED AND SURFACE CHEMISTRY OF CUTTING TOOLS ON THE FORMATION OF BUL OR BUE AND SURFACE QUALITY OF THE GENERATED SURFACE IN DRY TURNING OF AA6005 ALUMINIUM ALLOY

In the present investigation, AA6005 (ISO: AlSiMg) alloy was machined in turning operation with different cutting tools, such as uncoated cemented carbide insert, PVD TiN coated, CVD diamond coated and PCD insert, under dry environment. Effect of cutting speed was studied for each of the cutting tools with regard to the formation of built-up layer (BUL) or built-up edge (BUE). The rake surface of the tools was characterized by optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopic microanalysis. Particular emphasis was given on wear mechanism of PVD TiN coated insert, conventionally used in machining ferrous alloys, during dry turning of AA6005 alloy. It has been observed that increase of cutting speed from 200 m/min to as high as 1000 m/min could not substantially reduce formation of BUL over tool rake surface during dry machining of AA6005 alloy with uncoated or PVD TiN coated cemented carbide inserts. The potential of diamond-based tools in dry machining of aluminium alloy was also studied. Finally, the effect of cutting speed on surface finish of the workpiece machined with different cutting tools was studied during dry turning of AA6005 alloy.     

High-Speed Machining of Malleable Cast Iron by Various Cutting Tools Coated by Physical Vapor Deposition

The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched.In this paper,turning tests were conducted on cemented carbide tools with different coatings(a thick TiN/TiAlN coating,a thin TiN/TiAlN coating,and a nanocomposite(nc)TiAlSiN coating).All coatings were applied by physical vapor deposi-tion.In a comparative study of chip morphology,cutting force,cutting temperature,specific cutting energy,tool wear,and surface roughness,this study analyzed the cutting characteristics of the tools coated with various materials,and established the relationship between the cutting parameters and machining objectives.The results showed that in malleable cast iron machining,the coating material significantly affects the cutting performance of the tool.Among the three tools,the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force,the lowest cutting tempera-ture,least tool wear,longest tool life,and best surface quality.Moreover,in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions,the wear mechanism of the coated tools was found to depend on the cast iron being machined.Therefore,the performance requirements of a tool depend on multiple factors,and selecting an appropriately coated tool for a particular cast iron material is essential.     

Wear Characteristics of Diamond Tools in Machining Ceramics

Wear characteristics of natural diamonds used to machine ceramic materials at a depth of cut of 2 μm and a speed of 1600 m/min were investigated. The diamond tools used for the machining tests were inspected using the Laue back reflection technique and scanning electron microscopy (SEM). Wear characteristics of the diamond tools appeared to be influenced by the material properties of the ceramics being machined, the build-up on the tips of the diamond tools, and the crystallographic orientations of the diamond crystals. Three wear patterns were identified: single-flat wear, double-flat wear, and micro-chipping wear. The single-flat and double-flat wear patterns were primarily observed in machining silicon nitride and alumina; the microchipping wear pattern was observed in machining silicon carbide. The wear rate for the microchipping pattern was found to be one to two orders of magnitude higher than those for other wear patterns. Silicon nitride wore the diamond tools faster than alumina did; however, it often formed built-up lips which reduced the wear of the diamond tools.     

Experimental study of high-speed milling of SiCp/Al composites with PCD tools

In this paper, high-speed milling experiments on silicon carbide particle reinforced aluminum matrix (SiCp/Al) composites with higher volume fraction and larger particles were carried out using polycrystalline diamond (PCD) tools at dry and wet machining conditions. For comparison, a TiC-based cermet tool was also used in milling the same workpiece material at very low speed. Worn PCD and cermet tools were measured and extensively characterized by scanning electron microscopy at different machining conditions. Furthermore, the effect of cutting distance on milling force and surface roughness were also investigated. The results showed that the main tool wear mechanism in machining of this type of material was abrasion on the flank face, and it was verified that the TiC-based cermet tool was not suitable for machining SiCp/Al composites with higher volume fraction and larger particles due to the heavy abrasive nature of reinforcement.     

Process investigation on meso-scale hard milling of ZrO2 by diamond coated tools

This paper investigates the feasible machining of zirconium oxide (ZrO₂) ceramics, in the hard state, via milling by diamond coated miniature tools (from here on briefly indicated as meso-scale hard milling). The workpiece material is a fully sintered yttria stabilized tetragonal zirconia polycrystalline ceramic (Y-TZP). Diamond coated WC mills, 2 mm in diameter, four flutes and large corner radius (0.5 mm) are chosen as cutting tools, and experiments are conducted on a state-of-the-art micro milling machine centre. The influence of cutting parameters, including axial depth of cut (a_p) and feed per tooth (f_z), on the achievable surface quality is studied by means of a one-factor variation experimental design. Further tests are also conducted to monitor the process performance, including surface roughness, tool wear and machining accuracy, over the machining time. Mirror quality surfaces, with average surface roughness Ra below 80 nm, are obtained on the machined samples; the SEM observations of the surface topography reveal a prevailing ductile cutting appearance. Tool wear initiates with delamination of the diamond coating and progresses with the wear of the WC substrate, with significant effect on the cutting process and its performance. Main applications of this research include three dimensional surface micro structuring and superior surface finishing.     

清洁切削高温合金涂层刀具切削性能及加工表面完整性

针对高温合金高速干切削刀具磨损严重、加工表面质量差等突出问题,基于清洁切削技术,采用硬质合金涂层刀具进行高速铣削高温合金GH2132试验,研究干式切削、液氮不同喷射温度对涂层刀具切削性能以及加工表面完整性的影响规律,探究运用清洁切削高温合金来延长涂层刀具寿命和提高加工表面质量的可行性。研究表明：液氮低温切削GH2132时的切削合力随喷射温度的降低而增大,切削区温度在-150～-190℃喷射时已完全处于低温状态;随着液氮喷射温度的降低,刀具涂层剥落面积明显减小,且降低了黏结磨损和氧化磨损,在-150℃喷射条件下可获得较长的刀具寿命;加工表面粗糙度S_a在-30～-150℃喷射条件下获得较小值,随喷射温度的降低,加工硬化和残余拉应力分别增大和减小;与干式切削相比,液氮切削喷射温度在-150～-190℃下可显著延长涂层刀具寿命并提高加工表面质量。     

Performance studies of multilayer hard surface coatings (TiN/TiCN/Al2O3/TiN) of indexable carbide inserts in hard machining: Part-I (An experimental approach)

In recent years, hard machining using CBN and ceramic inserts became an emerging technology than traditional grinding and widely used manufacturing processes. However the relatively high cost factors associated with such tools has left a space to look for relatively low cost cutting tool materials to perform in an acceptable range. Multilayer coated carbide insert is the proposed alternative in the present study due to its low cost. Thus, an attempt has been made to have an extensive study on the machinability aspects such as flank wear, chip morphology, surface roughness in finish hard turning of AISI 4340 steel (HRC 47 ± 1) using multilayer coated carbide (TiN/TiCN/Al₂O₃/TiN) insert under dry environment. Parametric influences on turning forces are also analyzed. From the machinability study, abrasion and chipping are found to be the dominant wear mechanism in hard turning. Multilayer TiN coated carbide inserts produced better surface quality and within recommendable range of 1.6 μm i.e. comparable with cylindrical grinding. At extreme parametric conditions, the growth of tool wear was observed to be rapid thus surface quality affected adversely. The chip morphology study reveals a more favorable machining environment in dry machining using TiN coated carbide inserts. The cutting speed and feed are found to have the significant effect on the tool wear and surface roughness from ANOVA study. It is evident that, thrust force (Fy) is the largest component followed by tangential force (Fz) and the feed force (Fx) in finish hard turning. The observations yield the machining ability of multilayer TiN coated carbide inserts in hard turning of AISI 4340 steel even at higher cutting speeds.