镍-硼/金刚石超薄切割片的制备与性能

在氨基磺酸镍体系电镀液中添加不同浓度的三甲胺硼烷(TMAB),在阴极自旋转状态下利用复合电沉积方法制备不同质量分数的硼的镍-硼/金刚石切割片,探究镀液中不同质量浓度的TMAB对切割片晶体结构、硬度、耐磨性的影响。结果表明:阴极自旋转状态下制备的镍-硼/金刚石切割片中金刚石分布均匀;随TMAB质量浓度增加,镀层的晶粒尺寸减小、硬度增加、耐磨性提高。当TMAB质量浓度为3.0 g/L时,镀层基质金属的晶粒尺寸最小为6.84 nm,硬度最大为2 453.6 HV,磨损量最小为1.7×10-2 mm3,磨损宽度最小为665.4 μm。用厚度为28.3 μm的镍-硼/金刚石切割片切割(111)晶面的N型单晶硅片,硅片切割槽宽度为35.3 μm,切缝比为1.25,最大崩边尺寸为3.1 μm。      

电沉积超薄型金刚石外圆切割片的研制

随着大规模集成电路的发展,对硅片的要求越来越高。硅片切割为了提高精度和成品率,从七十年代中期开始,国外已由原来采用金刚石划片刀,激光划片刀发展到使用金刚石外圆切割片。这种外圆切割片在用计算机控制的专用切割机上使用。目前这是一种比较先进的硅片切割工艺。这种外圆切割片的规格为中φ50.8×0.025～0.050×40mm,即刀片的厚度为     

德国TRENKER公司推出--制作高精度金刚石切割片的新方法

半导体材料如硅、砷化镓等的高精密切割对金刚石切割片的精度和使用寿命要求极高。为了满足这种要求,德国TRENKER磨料磨具技术公司开发了一种制作这种专用金刚石切割片的新方法。这种金刚石切割片还可用于玻璃、宝石、陶瓷等材料的切割。     

大厚度工件电火花线切割加工多次切割腰鼓度成因研究

为研究往复走丝电火花线切割加工在大厚度工件多次切割时形成腰鼓度的成因,对厚度为185 mm的工件进行了多次切割实验,通过改变工作液电导率、电极丝走丝速度、修刀补偿量和电极丝直径等条件,对加工形成的腰鼓度进行了测试及分析。结果表明:大厚度切割过程中,两极之间的脉冲放电爆炸力是产生腰鼓度的主要原因,通过增加电极丝直径以提高电极丝截面惯矩,可减小因放电爆炸力对电极丝形成的挠度,从而减小腰鼓度误差值。     

回炉料切割系统在桥壳铸件生产中的应用

针对球墨铸铁大截面回炉料切割破碎难的问题展开了研究,用金刚石切割片的多工位切割专机代替传统的切割机和鳄式剪断机,可大幅度提高效率,降低工人的劳动强度,提高了切割作业过程中的安全性。     

一种不锈钢管切割器

正涉及一种不锈钢管切割器,包括箱体、安装板。在安装板与箱体的上侧开设有条形槽,安装板的上方垂直安装有支柱座,支柱座上通过转动轴安装有斜板,在斜板上安装有切割机,在切割机一侧安装有切割罩,在切割罩内设置有切割片,切割片过转轴与切割机输出轴相连,并在切割机上安装有手柄,手柄上斜向下安装有挡料板,在切割片的下方设置有两个导向     

CBN陶瓷超薄切割片的研究

研究了不同增韧方法下陶瓷超薄切割片强度的变化。采用普通低温陶瓷结合剂制成的产品在回转速度16 000 r/min时解体,用硼酸铝晶须增强的产品在24 000 r/min时解体,通过浸渍法渗入低熔点金属的产品在40 000 r/min时仍可正常使用。切割实验表明,浸渍金属的陶瓷超薄切割片在切割质量和数量上基本可以达到进口树脂复合结合剂超薄切割片的水平,可替代进口产品。     

铸铁干式加工过程中钎焊金刚石圆锯片磨损机理

采用Ni-Cr合金活性钎料,在高真空炉中实现金刚石与钢基体牢固的钎焊连接。借助扫描电镜、能谱分析仪和X射线衍射仪阐述真空钎焊金刚石的钎焊机理和界面特征,分析钎焊金刚石圆锯片在干式加工铸铁过程中磨粒的磨损特性。结果表明:在铸铁管加工方面,钎焊金刚石圆锯片表现出优越的高效切割性能,磨粒磨损主要以破碎为主,磨削高温引起切屑粘附在破碎磨粒表面;揭示在铸铁干式加工过程中金刚石磨粒表面出现轻微的石墨化磨损等现象;实验表明磨粒的强度依然能满足加工要求。研制出适用铸铁材料高效加工用的高锋利度、高强度、安全的钎焊金刚石切割片。     

超声切割SiC单晶时金刚石线锯磨损特性的研究

超声线锯切割SiC单晶时,金刚石线锯的成本仅次于SiC单晶材料本身的成本。建立了超声辅助切割SiC单晶时线锯受力模型,对线锯受力和失效形式进行了理论分析,并进行了相关试验,研究了工件进给速度对线锯偏角、切割方式对线锯磨损、切削液对线锯磨损以及磨粒破坏形式对线锯切割性能的影响规律。结果表明:工件进给速率及超声振幅增大,线锯易被拉断,但过小,切割效率会降低,要想通过增大工件进给速率提高效率,必须提高线锯强度,增大导轮直径,降低线速;超声辅助切割时线锯磨损可降低约40%;与自来水相比,使用Ecocool Resist EP微乳化液后线锯表面堵塞较严重;金刚石磨粒的微小破碎、有利于切割。     

超声切割SiC单晶时金刚石线锯磨损特性研究

超声线锯切割SiC单晶时,金刚石线锯的成本仅次于SiC单晶材料本身的成本。建立了超声辅助切割SiC单晶时线锯受力模型,对线锯受力和失效形式进行了理论分析,并进行了相关试验,研究了工件进给速度对线锯偏角、切割方式对线锯磨损、切削液对线锯磨损以及磨粒破坏形式对线锯切割性能的影响规律。结果表明：工件进给速率及超声振幅增大,线锯易被拉断,但过小,切割效率会降低,要想通过增大工件进给速率提高效率,必须提高线锯强度,增大导轮直径,降低线速;超声辅助切割时线锯磨损可降低约40%;与自来水相比,使用Ecocool Resist EP微乳化液后线锯表面堵塞较严重;金刚石磨粒的微小破碎、有利于切割。     

Effects of tool flank wear on orthogonal cutting process of aluminum alloy

The tool flank begins to wear out as soon as cutting process proceeds. Cutting parameters such as cutting forces and cutting temperature will vary with increasing degree of flank wear. In order to reveal the relationship between them, the theoretical situations of cutting process were analyzed considering the tool flank wear effect. The variation rules of cutting force, residual stress and temperature distributions along with the tool flank wear were analyzed comparing with the sharp tool tip. Through FEM simulation method, affections of the tool flank wear value VB on cutting forces, residual stress and temperature distributions were analyzed. A special result in this simulation is that the thrust force is more sensitive to tool flank wear, which can be used as a recognition method of tool condition monitoring. The FEM simulation analysis result agrees well with the experimental measuring data in public literatures and some experiments made also by the authors.     

The reliability analysis of a thin-edge blade wear in the glass fiber cutting process

This study shows that the reliability analysis of a thin-edge blade plays an important role in cutting glass fiber and explores the main effect of three cutting factors: the cutting speed, the cutting load, and the cutting volume. The effect of each cutting factor on the thin-edge blade wear, as determined by long glass fiber weight, and exceeding a value of 1%, as specified in the customer's requirements, was investigated. According to the experimental results, the thin-edge blade wear distribution approximated to a Weibull distribution, and the cumulative probability could be determined after nine iterations. This study also finds that there is a large positive correlation among the various thin-edge blade-wear values at different cutting speeds. However, the correlation is negative for the various thin-edge blade-wear values when cutting at load, and when cutting at different cutting volumes. It was observed also that the optimum cutting speed with minimum thin-edge blade wear is 1.9 m/s. The successful deployment of this study will be a significant factor in improving the cutting process and cutting quality.     

新型组合式金刚石圆锯片热应力分析

针对加工大幅面石材制品的市场需求,提出一种切割幅面达到其直径2／3的新型组合式金刚石圆锯片基体,并对其进行了结构、功能分析。针对圆锯片基体的适张处理,在考虑切削热影响的情况下,应用ANSYS对新型组合式金刚石圆锯片基体进行应力、变形分析。结果表明：组合式金刚石圆锯片基体受温度影响较大,由于切削热的存在产生了较大的热应力和变形量,最大热应力发生在结块焊接处及节块外边缘。最大为315MPa。应力分析为基体的适张处理和稳定性设计提供理论依据和参考。     

木材加工旋切刀和刨切刀材料及其热处理

木材加工旋切刀和刨切刀用7CrWMoVSi和5Cr8WMo2VSi钢是通用性刃钢,8Cr2W2MoVSi和6Cr6W3MoV2Si钢是新研制的超细碳化物刃钢。新钢种克服了碳化物粗化,可使刀具有高的锋利度和耐磨性。研究表明,8Cr2W2MoVSi钢淬火后剩余碳化物平均尺寸为0.33μm,回火后硬度为61.5～63.5 HRC;6Cr6W3MoV2Si钢淬火后剩余碳化物平均尺寸为0.5μm,回火后硬度为62～64 HRC。旋切刀和刨切刀的锋利度、耐磨性、抗冲击性及热硬性是主要的使用性能,既与刃钢的综合力学性能有关,也与碳化物细化相关。     

金刚石框架锯锯切研究（Ⅴ）—金刚石结块磨损特征

在对金刚石框架锯锯切加工动力学，锯切破碎机理模型和金刚石框架锯锯切加工石材时的切削力研究的基础上，通过金刚石锯条锯切石材的实验，测量并分析了金刚石结块磨损特征及其分类，金刚石结块磨损机理，金刚石结块磨损与加工时间，进给速度，石材种类，金刚石结块性能和锯条张紧力等因素的关系，提出了加工参数和金刚石结块的优选原则，研究结果为系统开发和改进金刚石工具提供了一个良好的基础，基于 这些结果，可改进结合剂，金刚石质量，金刚石浓度，金刚石粒度，结块尺寸和结块间隔。     

Corrosion mechanisms in the wood industry,especially caused by tannins

In order to improve the lifetime of cutting knives in the wood processing industry, a study has been undertaken to find out which wear process is primarily responsible for the reduction of the lifetime of steel blades. The examination of damaged surfaces of the cutting tools reveals mechanical damage at the cutting edges on one hand, but on the other hand pitting corrosion can be detected. It turned out that the corrosion impact reduces the lifetime of the cutting tools more than the mechanical loading, because a mechanically damaged steel blade can easily be repaired through grinding. But once the blade is subjected to pitting corrosion, it becomes useless because whenever the blade is reground, new holes due to pitting corrosion come to the surface again. Further investigations showed that the corrosiveness of different wood types is responsible for a major part of the damage, and that different woods have a different corrosive impact. One important goal of the present investigation is to learn more about the corrosive agents of different woods. It is revealed that tannin, a water‐soluble acid, which can be found in all woods in different concentrations, is responsible for the main part of the corrosive attack. In view of the above, the corrosion mechanism of steel blades caused by tannin is analyzed. During the cutting processes in the industry the blade temperature is increased. Thus, it is aimed to evaluate the influence of higher temperatures on tannin and the pH value of the acid. It is also revealed that the additional mechanical stress has an important influence on the corrosion process. The investigation could satisfactorily show the lowering of the pH value of tannin acid at higher temperature, which leads to increased corrosion. It is also revealed that the additional mechanical stress causes off stripping of tannin–Fe complexes from the steel surface, there the steel was not able to build a protective layer yet. That also leads to a further increase in corrosion.     

金刚石颗粒在锯切石材过程中磨损形态的研究

本文分析和归纳了锯切花岗石过程中金刚石颗粒的五种磨损形态和三个磨损阶段，探讨了金铡石颗粒磨损形态对金刚石锯片锯切性能的影响。     

轴向超声振动辅助铣削TiB2/7050Al复合材料残余应力试验研究

针对TiB2颗粒增强铝基复合材料可加工性差、切削温度高、刀具磨损严重等问题,开展TiB2/7050Al复合材料轴向超声振动辅助铣削残余应力试验,研究各加工参数对超声振动辅助铣削表面及亚表层残余应力的影响规律,并分析力热耦合作用对超声振动辅助铣削残余应力的作用机制。研究表明:TiB2/7050Al复合材料超声振动辅助铣削表面残余应力均为残余压应力,且残余压应力随每齿进给量、切削速度的增加而减小,而随着切削深度及超声频率的增加呈现先增大后减小的趋势;工件亚表层残余应力影响层厚度为90~120μm,且未观测到明显的加工硬化现象。     

Thermal and mechanical modeling analysis of laser-assisted micro-milling of difficult-to-machine alloys

This study is focused on numerical modeling analysis of laser-assisted micro-milling (LAMM) of difficult-to-machine alloys, such as Ti6Al4V, Inconel 718, and stainless steel AISI 422. Multiple LAMM tests are performed on these materials in side cutting of bulk and fin workpiece configurations with 100-300 μm diameter micro endmills. A 3D transient finite volume prismatic thermal model is used to quantitatively analyse the material temperature increase in the machined chamfer due to laser-assist during the LAMM process. Novel 2D finite element (FE) models are developed in ABAQUS to simulate the continuous chip formation with varying chip thickness with the strain gradient constitutive material models developed for the size effect in micro-milling. The steady-state workpiece and tool cutting temperatures after multiple milling cycles are analysed with a heat transfer model based on the chip formation analysis and the prismatic thermal model predictions. An empirical tool wear model is implemented in the finite element analysis to predict tool wear in the LAMM side cutting process. The FE model results are discussed in chip formation, flow stresses, temperatures and velocity fields to great details, which relate to the surface integrity analysis and built-up edge (BUE) formation in micro-milling.     

Effect of PVD films wet micro-blasting by various Al2O3 grain sizes on the wear behaviour of coated tools

Micro-blasting on PVD films has been documented, among others, as an efficient method for inducing compressive stresses, thus for increasing the coating hardness and potentially tool life of coated tools. Since contradictory results have been registered concerning the efficiency of wet micro-blasting on coated tools for improving the wear behaviour, the paper aims at explaining how this process can be successfully applied for post-treatment of PVD films. In this context, the employed conditions such as pressure and grain size affect significantly the wear resistance of the micro-blasted coated tools.In the described investigations, TiAlN coatings were post-treated through wet micro-blasting by Al₂O₃ abrasives of various grains' diameter. Abrasion mechanisms after micro-blasting were investigated by roughness measurements. Nanoindentations on micro-blasted film surfaces at various pressures revealed the influence of this process on coating superficial hardness. The related residual stress changes were estimated considering the film yield stress alterations, which were analytically determined, based on nanoindentation results. Nano-impact tests were conducted for investigating the effect of the developed film compressive stresses at certain micro-blasting pressures and grain sizes on the film's brittleness. To monitor film thickness and cutting edge radius changes of coatings subjected to micro-blasting, ball cratering tests and white light scans were carried out respectively. In this way, micro-blasting conditions for improving the film hardness, without revealing the substrate in the cutting edge region, were detected. Finally, the wear behaviour of coated and variously wet micro-blasted tools was investigated in milling of hardened steel.