硬质合金PCB微铣的磨损性能研究

随着现代电子产品的高速发展,对于PCB板的切削加工的需求量也越来越大。本文从刀具寿命及刀具的磨损形式两个方面,对比了两种不同型号的PCB铣刀的使用性能。结果表明对于PCB铣刀,在加工初期切削刃上会出现破损,随着加工过程的进行,该破损会增大。加工过程中在切削刃上会附着粉末,这些粉末会加剧铣刀的磨损,导致断刀。两种刀具比较而言RSF028的刀具的平均寿命以及寿命数据都比RSE027的要好一些。     

A880高压动叶片型面加工R5球头铣刀磨损机理与寿命研究

针对X22CrMo V12-1-5钢汽轮机A880高压动叶片型面加工R5球头铣刀磨损机理及寿命进行研究。通过模拟现场工况下的R5球头铣刀磨损实验得到刀具磨损曲线和刀具寿命,分析了R5球头铣刀的磨损失效机理,得到R5球头铣刀最大不崩刃许用切削长度和铣刀全寿命周期中可以加工的叶片数目。利用所得到的R5球头铣刀寿命量化模型对加工现场报废的R5球头铣刀做了剩余寿命挖掘,研究发现加工现场报废的刀具仍然具有较大的使用价值并根据模型预测了其剩余寿命。研究结论可应用于实际生产中R5球头铣刀的寿命管理,大幅度提高实际加工中R5球头铣刀的使用效率。     

硬质合金PCB微铣刀具的磨损性能分析

在科技不断进步的过程中,对于高精度的产品有着越来越高的要求,电子产品的使用范围也得到了很大的拓展。在本文中,我们以电子行业中PCB板的切削加工为例,详细的讨论了刀具在使用寿命和使用方式,同时对于PCB微铣刀具在使用过程中出现的磨损现象进行讨论。根据研究发现,在加工中,硬质合金PCB微铣刀具在切削刃上容易出现破损的情况,如果加工的强度不断的增加,破损的概率也会相应的提高。最初的破坏会在切削刃上出现一些粉末状的物质,这些物质在切削过程中参与了微铣刀具的切磨过程,直接加剧了微铣刀具的磨损程度,最终形成断刀的情况,对于这样的情况就需要对于刀具进行改良,寻求更好的刀具来完成加工任务。     

断续切削对铣刀刀具寿命的影响

断续切削对铣刀磨损危害严重,影响刀具使用寿命。通过对叉形块零件进行测试加工,对比先加工孔后加工槽与先加工槽后加工孔两种加工情况下的铣刀寿命。最终得出断续切削对铣刀寿命的影响程度。     

金属陶瓷铣刀加工灰铸铁的试验研究

精加工灰铸铁零件时,对被加工零件表面光洁度要求较高。采用硬质合金刀具加工时刀尖处易磨损,影响零件表面光洁度,且硬质合金铣刀的寿命较低。分析实际加工条件和被加工材料的特征后,改用金属陶瓷铣刀后进行试验,刀具寿命延长较多,加工效率也有所提高。     

运用刀具在线监控技术优化汽轮机轮槽刀具寿命

通过刀具在线监控技术监控分析汽轮机轮槽铣刀在切削加工镍基高温合金中的状态,研究刀具在切削加工中的磨损规律,得出优化刀具寿命的可行性方法,以提高刀具的切削寿命。试验结果表明,通过调整刀具的切削参数可提高刀具的切削寿命。     

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。     

铣刀磨损对机床箱体结合面加工质量影响分析

通过对刀具齿数、刀具切削参数两个变量的更改,验证了以上两个因素的改变对铣刀磨损的影响,及铣刀磨损程度对结合面加工质量的影响。为完善刀具磨损对结合面铣削加工质量影响研究提供参考。     

渗硫刀具的应用

我们首先对指状铣刀进行了渗硫技术应用试验。用指状铣刀在3m滚齿机上加工40Cr四辊弯板机的内齿圈,粗铣时,原来的一把铣刀只能加工10个齿。为了提高刀具寿命,我们将指状铣刀进行了渗硫处理。处理后的铣刀每把可加工30个齿。刀具寿命提高了2倍。精铣时,原米每把铣刀只能加工15个齿,精加工一个齿圈要换刀6次。每次换刀由于齿形有变化很容易造成废品。用渗硫处理的铣刀每把可加工110个齿,刀具寿命提高6.4倍。由于避免了加工中换刀,大大提高了加工质量,而且还可提高生产效率50％(表1)。     

微细铣削加工刀具磨损数值模拟的研究

采用商业有限元DEFORM-3D软件,建立了三维微细铣削加工模型,利用该模型动态模拟了硬质合金微径铣刀铣削加工2A12工件时刀具的磨损变化形态。结果表明,与常规刀具磨损形态不同,微径铣刀的磨损主要发生在刀尖处,后刀面磨损形态为近似三角形。针对这一特点,提出利用后刀面刀尖处的最大磨损高度hmax判断微径铣刀磨损量的方法,研究铣削方式对刀具磨损量影响的变化规律。仿真结果可用于预测刀具磨损变化规律,为微细铣削加工参数的优化、微径铣刀的合理选用、设计及进一步有效控制刀具磨损提供研究手段。     

Tribological compatibility and improvement of machining productivity and surface integrity

Machining process productivity and machined part quality improvement is a considerable challenge for modern manufacturing. One way to accomplish this is through the application of PVD coatings on cutting tools. In this study the wear rate and wear behavior of end milling cutters with mono-layered TiAlCrN and nano-multilayered self-adaptive TiAlCrN/WN PVD coatings have been studied under high performance dry ball-nose end-milling conditions. The material being machined in this case is hardened H13 tool steel. The morphology of the worn surface of the cutting tool has been studied using SEM/EDX. The microstructure of the cross-section of the chips formed during cutting was analyzed as well. The surface integrity of the workpiece material was also evaluated. Surface roughness and microhardness distribution near the surface of the workpiece material was also investigated. The data presented shows that achieving a high degree of tribological compatibility within the cutting tool/workpiece system can have a big impact on tool life and surface integrity improvement during end milling of hardened tool steel.     

Cutting tests for end-milling radius cutters of high-speed steel with and without diffusion coating

Results of laboratory cutting tests of an end-milling radius cutter of R6M5 high-speed steel with a diffusion complex coating (C-B-N) and without coating are given. The relationship between the wear kinetics and tool life is determined. Under the accepted test conditions, the tool life with coating is shown to be 1.6 times higher than the tool life of similar milling cutters without coating. The higher tribological stability of the coating in the course of wear is verified by the results of electron-microscope analysis of the worn surfaces of milling cutters.     

基于有限元仿真的拼接模具铣削用刀具优化

对ABAQUS软件进行了二次开发，以实现拼接模具铣削过程仿真前处理的快速建模。对铣削力、应力和刀具温度进行仿真，并与铣削实验结果对比，验证了仿真模型的准确性。对不同前角、后角、螺旋角及刃口半径的球头铣刀铣削拼接模具的过程进行模拟仿真，采用遗传算法优化铣刀结构，将优化后的结构参数与传统结构参数代入刀具磨损、工件表面质量的对比实验，从而验证了优化的有效性。研究表明，对仿真前处理进行快速建模的二次开发运行成功，模拟结果准确。研究结果为降低制造成本、提高铣刀寿命和工件表面质量提供了理论参考。     

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.     

An Operation Planning System for Multi-Axis Milling of Sculptured Surfaces

Multi-axis milling of sculptured surfaces with cylindrical or toroidal cutters has many advantages compared to the use of three-axis milling with ball nose cutters. Surfaces to be machined are often of complex shape and characterised by convex, concave and saddle areas. Today, CAM-systems do not support the user in the selection of the different operations in order to finish the workpiece. This paper describes an operation planning system, which facilitates process planning for the multi-axis machining of sculptured surfaces. The core of the system is surface analysis, which divides the surfaces into regions, each characterised by a preferred milling direction and tool diameter. Further, for each region or set of regions, a drive surface is constructed that is used as the basis for the tool-path calculation. The drive surface approximates to the original workpiece as closely as possible, and the isoparametric lines which will be the tool-path feed direction lie in the preferred milling direction.     

Life prediction system using a tool’s geometric shape for high-speed milling

In recent years, machinery and tool technology has been developing rapidly. The accuracy of operations have also become more and more exact. Elsewhere, raw materials have also been honed, hoping to provide more useful properties than previously. Thus, how to find the best way to prolong the life of a tool subjected to hardened material cutting is the target of this research. Three kinds of tool angle of the endmill are used in this research; clearance angle, rake angle, and helical angle. The cutting conditions are the same; we only change the tool angle for all the cases studied. We attempt to discover better tool geometrical angles for the high-speed milling of NAK80 mold steel. The tool wear rate was measured through a toolmaker’s microscope and the roughness of the machined surface was measured by the roughness-measuring instruments after several complete surface layers were removed from the workpiece in the experiment. Also, a noise-mediator was used to detect the level of cutting noise during each surface layer workpiece removal of the high-speed milling process, and different noise levels were then compared with the tool wear rates for identifying noise characteristics in the case of an over-worn tool state. An abductive network was applied to synthesize the data sets measured from the experiments and the prediction models are established for tool-life estimation and over-worn situation alert under various combinations of different tool geometrical angles. Through the identification of tool wear and its related cutting noise, we hope to consequently construct an automatic tool wear monitoring system by noise detection during a high-speed cutting process to judge whether the tool is still good or not, and, so, the cost of milling can be reduced.     

铣削TC4钛合金的刀具磨损对比试验

TC4钛合金是典型难加工材料之一,极易造成工具磨损。本文通过铣削TC4钛合金试验,跟踪铣削过程中铣刀每个齿的磨损量及磨损形态,比较了不同细晶粒硬质合金铣刀的磨损过程。结果表明,铣刀切削刃发生崩刃会直接缩短铣刀的使用寿命。     

CONDITION MONITORING FOR INDEXABLE CARBIDE END MILL USING ACCELERATION DATA

In order to automate machining operations, it is necessary to develop robust tool condition monitoring techniques. In this paper, a tool monitoring strategy for indexable tungsten carbide end milling tools is presented based on the Fourier transform and statistical analysis of the vibrations of the tool during the machining operations. Using a low-cost, tri-axial piezoelectric accelerometer, the presented algorithm demonstrates the ability to accurately monitor the condition of the tools as the wear increases during linear milling operations. One benefit of using accelerometer signals to monitor the cutting process is that the sensor does not limit the machine's capabilities, as a workpiece mounted dynamometer does. To demonstrate capabilities of the technique, four tool wear life tests were conducted under various conditions. The indirect method discussed herein successfully tracks the tool's wear and is shown to be sensitive enough to provide sufficient time to replace the insert prior to damage of the machine tool, cutter, and/or workpiece.     

PCBN刀具的磨损机理和干切削GCr15时的磨损与寿命

研究了PCBN刀具的磨损机理和磨损形式。通过对干切削GCr15轴承钢时刀具的磨损形式及寿命进行试验研究 ,得出了工件硬度、切削速度对PCBN刀具磨损的影响规律以及工件硬度在临界硬度附近时刀具磨损速度最快的结论。加工两种硬度工件时的刀具寿命方程表明 ,切削速度对PCBN刀具寿命的影响小于对硬质合金及陶瓷刀具寿命的影响。     

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.