PCD刀具最小刃磨余量的研究

利用扫描电镜观察激光切割与线切割对PCD复合片表面形貌的影响 ,了解不同切割方式对PCD层造成热损伤的特点 ,估计了切割方式对PCD的损伤深度 ,并据此确定其刀具刃磨的最小加工余量。试验结果表明 :激光切割的PCD复合片 ,最小刃磨余量约为 10 μm ;EDM切割的PCD复合片 ,最小刃磨余量约为 15～ 2 0 μm。     

聚晶金刚石复合片的电火花线切割机理与形貌

开展了聚晶金刚石复合片（PDC）的电火花线切割实验，提出了PDC的电火花线切割模型。通过扫描电镜与拉曼光谱仪对切割试件进行显微观察与成分分析，发现聚晶金刚石层表面存在明显石墨化现象，而且聚晶金刚石层与硬质合金层之间的富钴界面层存在严重过量去除现象。按聚晶金刚石层、富钴界面层与硬质合金层三个部分剖析了PDC放电蚀除机理，并对PDC的电火花线切割热损伤进行了分析。研究表明，解决富钴界面层的过量去除问题是提高PDC电火花线切割加工质量的关键。     

金刚石刀具与刃磨技术研究现状

简述了金刚石刀具的应用领域,介绍了聚晶金刚石(PCD)刀具刃磨技术及设备的研究现状,分析了影响金刚石机械刃磨质量的主要因素,认为特种加工与机械刃磨相结合的复合刃磨技术是金刚石刀具刃磨的重要发展方向。     

聚晶金刚石复合片激光抛光工艺研究

聚晶金刚石复合片因具有超高硬度、耐磨性和良好的热稳定性,被广泛用作切削加工的刀具材料。利用PCD复合片制作刀具时,和传统加工工艺相比,激光抛光可以获得更良好的加工特性。为探究PCD复合片的激光抛光工艺特性,获取最佳表面粗糙度,利用飞秒已抛光区域的线粗糙度,系统地研究了激光功率、扫描速度、扫描间距的水平变化对粗糙度和抛光效率的影响规律。采用正交试验方法对3个因素水平进行优化组合,同时对飞秒激光抛光PCD的作用机理进行初步探究。结果表明：影响粗糙度的主要因素为扫描速度,选用7 MW激光功率、1 000μm/s扫描速度、12μm扫描间距的工艺参数可以获得粗糙度为33.95 nm的优良PCD复合片。     

金刚石刀具材料粒度、磨削砂轮粒度与刃口质量的关系

聚晶金刚石(PCD)刀具由于其自身的高硬度、高耐磨性的特征,使得刃磨加工极易出现崩刃——呈锯齿状刃口的典型缺陷,因此其机械磨削加工较其它刀具材料来看难度更大。本文针对金刚石刀具常用的加工方式——金刚石砂轮机械刃磨展开试验,主要针对金刚石刀片自身材料颗粒度与磨削砂轮粒度这两方面进行研究。通过收集数据,分析对比,研究金刚石材料颗粒度、磨削砂轮粒度对刀具最终刃口质量的影响。     

薄镍板上Meso尺度结构的电火花线切割

研究了利用常规电火花线切割技术加工薄镍板微小结构的方法.利用慢走丝电火花线切割加工机床对厚度为0.6 mm镍板上的Meso尺度结构进行了加工试验.以机床现有的工艺条件对零件进行试切割,对试切割后的尺寸精度和表面质量进行测量分析,在此基础上通过对放电能量、冲液压力、切割速度等机床参数的调整改进加工工艺.探讨了在200 μm缝宽范围内进行多次切割的方法,并对切割次数进行合理优化、合并.试验结果表明:慢走丝线切割加工对小于机床设定厚度的薄板Meso尺度结构仍可进行稳定加工;通过多次切割的方法可提高表面质量.在200μm窄缝范围内进行5次常规切割,加工后的表面粗糙度值Ra为0.54 μm;在保证表面质量的前提下,将5次切割合并为3次切割,加工后的表面粗糙度值Ra为0.62 μm,加工时间缩短了30％左右.该技术可为电火花线切割加工其他材料薄板微小零件提供支持与参考.     

聚晶金刚石复合片磨削力研究

聚晶金刚石复合片有高硬度和良好的韧性,是理想的刀具材料.采用金刚石砂轮对聚晶金刚石(PCD)复合片材料的聚晶金刚石层进行了磨削试验,研究了磨削工艺参数和砂轮特性对磨削力的影响.     

聚晶金刚石复合片快速切割技术

聚晶金刚石(PCD)是人造最硬的物质,硬度高,耐磨性好,是制造石油地质钻头、电线电缆模具、切割工具等的理想材料。 聚晶金刚石在制成工具时,常与硬质合金(WC)烧结在一起制成复合材料——聚晶金刚石复合片,然后再将它切割成所需的形状,制成各种各样的工具。然而由于它硬度高、熔点高、电阻率高、耐磨性高,采用机械成形加工非常困难,采用普通的电火花线切割加工也有一定的困难。 本项切割技术是在北京市电加工研究所获国家发明二等奖、日内瓦国际新发明银奖“聚晶金刚石加工技术”的基础上,结合为美国GE公司加工φ50.8mm的紫晶金刚石复合片开始的,针对如何快速切割高质量的聚晶金刚石复合片,在机械装置和加工工艺方面作     

金刚石飞切加工微结构表面的工艺参数优化

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300'超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响.理论分析表明,金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化.减小进给量和金刚石飞刀前端角或增大切削半径可以降低理论粗糙度值.实验分析表明,表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大.切削聚碳酸酯(PC)时,在5～40 μm Ra随背吃刀量的增加而增加;而切削铝合金(LY12)时,在2～10 μm Ra随背吃刀量的增加而减小.实验中Ra最好可达38 nm(LY12)和43 nm(PC).最后,利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构.     

CVD金刚石厚膜刀具切削性能的试验研究

分析了CVD金刚石厚膜刀具材料的性能特点 ,对CVD金刚石厚膜车刀进行了精密切削和难加工复合材料切削试验 ,结果表明 :CVD金刚石厚膜刀具加工铝合金的表面粗糙度可达Ra0 0 5 μm ;切削难加工复合材料时刀具耐磨性和使用寿命明显优于硬质合金刀具、PCBN刀具和PCD刀具     

Electrical discharge grinding of polycrystalline diamond – Effect of wheel rotation

Electrical Discharge Grinding (EDG) is an advanced machining process that becomes popular in manufacturing of Polycrystalline Diamond (PCD) tools. This research investigated the effects of wheel rotation as well as debris flow direction on the quality of PCD tools based on a series of EDG experiments. Experimental results showed the debris that flowed toward the cutting edge could significantly affect the edge sharpness and symmetry of the tool, which were critical for the smaller edge apex angle. Evidence of spark concentration caused by the debris accumulation phenomenon were found through microscopic analysis on the eroded surfaces. This research also revealed the unexplained phenomenon associated with the undercut that normally formed beneath the PCD cutting edge after erosion. By examining PCD samples using scanning electron microscopy (SEM) and Raman spectroscopy, the formation of the heat-affected layer caused by the high-temperature erosion process in the EDG was analyzed. Results also proved that the surface finish of tungsten carbide (WC) and notch width of the PCD tools, particularly on the tungsten carbide WC/PCD interface, should not be taken as the index to measure PCD tool quality.     

Application of Taguchi and response surface methodologies for surface roughness in machining glass fiber reinforced plastics by PCD tooling

This paper discusses the use of Taguchi and response surface methodologies for minimizing the surface roughness in machining glass fiber reinforced (GFRP) plastics with a polycrystalline diamond (PCD) tool. The experiments have been conducted using Taguchi’s experimental design technique. The cutting parameters used are cutting speed, feed and depth of cut. The effect of cutting parameters on surface roughness is evaluated and the optimum cutting condition for minimizing the surface roughness is determined. A second-order model has been established between the cutting parameters and surface roughness using response surface methodology. The experimental results reveal that the most significant machining parameter for surface roughness is feed followed by cutting speed. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the surface roughness in the machining of GFRP composites. The predicted values are confirmed by using validation experiments.     

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.     

制备PCD刀具的关键工序

随着中国汽车工业的高速发展,PCD刀具被广泛应用于以发动机和变速箱为代表的汽车零部件加工。对于PCD刀具,特别是各种高精度、非标准复合PCD刀具,PCD复合片的焊接、PCD刀具的线切割和刃磨等关键工序在很大程度上决定了PCD刀具的加工精度和刀具寿命。本文主要研究了PCD刀具的焊接、线切割和刃磨等关键工序。     

PCD刀具金刚石砂轮刃磨表面质量及其对加工工件表面质量的影响

对树脂结合剂、金属结合剂和陶瓷结合剂金刚石砂轮刃磨PCD刀具的过程特点进行了比较分析,认为陶瓷结合剂金刚石砂轮刃磨PCD刀具可以得到较好的刃磨表面质量且刃磨效率最高;同时对加工工件表面的形成过程进行了分析,认为PCD刀具的后刀面表面质量是最重要的影响因素。     

Machinability aspects concerning micro-turning of PA66-GF30-reinforced polyamide

This paper aims to study the behavior of machining forces and machined surface finish when micro-turning PA66-GF30-reinforced polyamide with various tool materials under distinct cutting conditions. The performance of polycrystalline diamond (PCD), CVD diamond coated carbide and plain cemented carbide tools (K15-KF and K15) were investigated in addition to the influence of feed rate on cutting forces, surface roughness and chip formation. The results indicated that the radial force was the highest force component because of the reduction in the effective cutting edge angle. Moreover, the cutting force increased almost linearly with feed, whereas the feed and radial forces remained unaltered. The cutting tools possessing lower edge radius promoted lower surface finish and turning forces, i.e., the best results were provided by the PCD tool, followed by the uncoated carbide inserts and finally by the CVD diamond-coated carbide tool.     

全陶瓷球轴承套圈沟道精密磨削用砂轮修整试验

为提高金刚石圆弧砂轮外缘轮廓精度,减少全陶瓷球轴承套圈沟形误差,采用金刚石碟片对树脂基金刚石圆弧砂轮进行修整;对比修整前后砂轮的表面形貌及套圈沟形误差,验证砂轮的修整效果.修整后砂轮表面出现光泽,露出表面的金刚石磨粒明显增多,部分金刚石磨粒破碎,形成新切削刃或脱落,增大容屑空间;修整前沟形误差的平均值为5.823μm,...