高性能CVD金刚石薄膜涂层刀具的制备和试验研究

采用电子增强热丝EACVD法,以WC-Co硬质合金刀具为衬底制备金刚石涂层刀具,研究了提高涂层附着力的衬底预处理新方法,探讨了抑制Co催石墨化作用的有效措施,提出了改善金刚石薄膜表面粗糙度CVD后处理新工艺。研究结果表明,采用了Ar-H2微波等离子体刻蚀脱碳预处理方法对于提高金刚石薄膜涂层的附着力有明显效果,添加适量粘结促进剂,可有效地抑制CVD沉积过程中钴向表层扩散引起的催石墨化作用。采用分步沉积新工艺是减小金刚石薄膜表面粗糙度的有效方法。所制备的高附着力和低粗糙度的金刚石薄膜涂层刀具切削性能明显改善,对实现高效高精度切削加工具有十分重要的意义。     

新型陶瓷涂层硬质合金刀具的涂层机理和切削性能

以异丙醇铝为前驱物,将溶胶-凝胶工艺应用于硬质合金刀片涂层,研制成功一种新型的陶瓷涂层刀片,从而为涂层刀具制造展示了一种全新的涂层方法。使用浸渍提拉法对刀具基体进行涂层,然后经凝胶、干燥和1200℃热处理后可以得到厚度适宜的α－Al2O3涂层,涂层完整,无宏观缺陷,并且在初步的切削试验中显示出一定效果。涂层在1140℃左右转化成α－Al2O3,在1200℃烧结致密,而在1250℃以上涂层发生明显收缩,晶粒明显长大,最终的涂层为多晶体结构,涂层界面未生成弱化相,硬质合金中的部分钴元素扩散到涂层中,有助于提高涂层和基体间的粘结强度。切削试验的结果表明,所得涂层能有效地阻止前刀面上的粘结磨损,从而提高了刀具的使用寿命。     

THE EFFECT OF THE CUTTING FLUID ON SURFACE ROUGHNESS IN BORING OF LOW CARBON STEEL-TECHNICAL COMMUNICATION

In spite of their environmental and human health problems, the cutting fluids still have been used widely in industry due to cutting fluid application can increase cutting performance in metal cutting. In this article, the effect of the cutting fluid on surface roughness in boring of AISI 1030 low carbon steel was investigated depending on BUE and chip formations and other cutting parameters, such as cutting speed, feed rate and tool nose radius. In most of boring experiments, the wet cutting did not show more preferable results than dry cutting. However, cutting fluid application with big nose radius and small feed rate improved the surface roughness up to 80%. This progress was attributed to a favorable chip formation as much as effective cooling.     

密封系统性能的表面粗糙效应试验研究

分析了密封系统中硬对偶件表面粗糙特性对密封系统工作性能的影响,揭示了在相对运动密封零件表面间摩擦学过程中出现的微观曲路密封效应和微观跑合效应,为通过控制密封系统中硬对偶件表面加工工艺以形成优秀的表面形貌,来提高密封系统的工作性能提供了新的思路和概念。     

MACHINABILITY OF AI/SiC PARTICULATE METAL-MATRIX COMPOSITES UNDER DRY CONDITIONS WITH CVD DIAMOND-COATED CARBIDE TOOLS

This article investigates the machinability of two Al/SiC particulate metal-matrix composites (MMC) with 5 and 15% vol. SiC particles. Dry turning tests were performed with three different CVD diamond-coated tools. In a first series of experiments, various cutting conditions were tested and their effects on tool wear mechanisms were studied. For the second series, optimal cutting conditions were chosen and tool life was investigated. The consumed spindle power was continuously measured; it was shown that its increasing follows the evolution of the tool wear criteria. Residual stresses at the machined surfaces were measured by X-ray diffraction technique. The effect of SiC percentage in the MMC on the machinability was also investigated.     

模具粗糙度对板材拉延件摩擦特性的影响

金属板材拉延是一个复杂的塑性变形过程,广泛应用在各种大型汽车覆盖件等零件生产中。介绍了金属带料弯曲拉伸试验机的工作原理和试验方法。该试验机能很好地模拟凹模圆角区的摩擦场变化规律;通过选用不同的模具表面粗糙度,改变带料拉伸力、变形速度和成形头平均面压,测出摩擦因数的变化规律,用以研究模具表面粗糙度等对板材拉延件摩擦特性的影响。研究表明,适当降低模具表面粗糙度,有利于发展边界润滑,减少摩擦热的产生和作用。该研究方法把拉延过程中的摩擦、磨损和润滑有机地结合起来,为优化拉延件加工的摩擦条件奠定了理论基础。     

金刚石砂轮的CO2脉冲激光修锐研究

利用CO2激光对树脂结合剂金刚石砂轮片的表面进行了扫描试验,对扫描前后砂轮片的表面三维形貌进行了测试分析,研究了激光脉冲频率和占空比等参数的影响。结果表明,尽管平均扫描能量密度一定,但频率和占空比对修锐效果均会产生影响,其中频率的影响更为显著。同时,通过使用铝工件和砂轮片的相对刻划试验,对不同扫描条件下刻划时的切向力与法向力之比进行了对比分析,发现由于该力比可以有效地反映出砂轮片的切削性能,因此可以用来对修锐效果进行定量评价。     

基于遗传算法的超精密切削表面粗糙度预测模型参数辨识及切削用量优化

建立易于分析各切削用量对粗糙度影响关系的表面粗糙度预测模型和最优的切削用量组合,是超精密切削加工技术的不断发展的需要。针对最小二乘法和传统优化方法的不足,提出了将遗传算法用于超精密切削表面粗糙度预测模型的参数辨识,并用于求解最优切削用量,给出了金刚石刀具超精密切削铝合金的表面粗糙度预测数学模型和切削用量优化结果,进行了遗传算法和常规优化算法的比较,结果表明遗传算法较最小二乘法和传统的优化方法更适合于粗糙度预测模型的参数辨识及保证切削用量的最优。     

金刚石及金刚石涂层中固体粒子冲蚀裂纹的发生发展行为

应用多粒子连续冲击方法研究天然金刚石和金刚石涂层的固体粒子冲蚀特性，研究其中冲蚀裂纹的发生发展行为，并应用弹性理论作了分析，理论计算结果与实验结果符合良好。     

易切削相组成、形态及面积份数对硫系易切削钢切削性能的影响

研究了Ca、RE及Ca-RE变性后易切削相的组成、形态及面积份数对硫系易切削钢切削性能的影响。降低切削力的作用依MnS、（Mn、Ca）S、MnS-RE2S3及（Mn、Ca）S-RE2S3次序减弱,而减少后刀面磨损的作用按上述次序增强。易切削相形态的改善对前者不利,而对后者有利,面积份数的增加对两者都有利。     

纳米金刚石薄膜的制备与应用

采用偏压辅助增强热丝化学气相沉积法(Chemical vapor deposition,CVD),以WC-Co硬质合金为衬底,采用控制沉积参数和添加惰性气体Ar等CVD新工艺,制备性能优良的纳米金刚石薄膜.进一步采用扫描电镜(Scanning electron microscopy,SEM)、原子力显微镜(Atomic force microscopy,AFM)、拉曼光谱(Raman spectroscopy)、X射线衍射(X-ray diffraction,XRD)和高分辨率透射电镜(High-resolution transmission electron microscopy,HR-TEM)分析了薄膜的纳米效应.研究结果表明:纳米涂层仍然是以金刚石结构为主的多晶体,它晶体颗粒较小(20～80 nm),含有较多的晶界和sp2结构,涂层表面粗糙度Ra≤50 nm,表面平整光滑,有利于研磨抛光.在此基础上,提出纳米金刚石复合涂层制备新技术,开发研制出各种涂层拉拔模具,在实际生产线上进行了应用,取得了显著的效果.     

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     

用CVD金刚石厚膜车刀加工硬质合金的研究

采用CVD金刚石厚膜车刀对K10硬质合金进行了不同安装前角下的切削加工试验,比较分析了刀具的磨损状况和加工表面粗糙度随前角的变化规律。结果表明,增大车刀安装前角的负值,可以抑制切削刃边缘的破碎及直线刃部的剥离破碎,提高工件的加工表面质量。     

轴向车铣加工的运动学建模与理论表面粗糙度分析

给出了轴向国铣运动的数学模型,并在此基础上对轴向车铣的运动规迹及共工件理论表面粗糙度进行了分析。     

ROUGHNESS VARIATION CAUSED BY GRINDING ERRORS OF CUTTING EDGES IN SIDE MILLING

A numerical model was developed to predict the roughness profile along a line in the feed direction, in contour milling operations with cylindrical milling tools. From the model, average roughness R_a and maximum peak-to-valley roughness R_t were calculated for families of tools defined by 100,000 random combinations of radius values. Radii were selected by means of the Monte Carlo Method. Each family is defined by an average radius and a standard deviation of radius, assuming normal behavior. Histograms, roughness variation intervals, medians and modes, were calculated at different feeds. The model was validated through experimental tests. Effect of standard deviation of radius, number of teeth and tool diameter were studied. Although radius values were randomly selected according to a normal law, roughness values did not follow a normal distribution. At low standard deviations, intervals of roughness values, medians and modes vary only slightly with feed, except at very low feeds where intervals are narrow. On the contrary, at higher standard deviations, median, mode and width of roughness intervals rise as feed increases. Use of a lower number of teeth and higher tool diameter leads to narrower intervals and asymmetrical roughness frequency distributions even at high feeds, with modes near upper reference values.     

Experimental investigation on cutting mechanisms in fixed diamond wire sawing of bone

Bone sawing has been widely used in performing bone surgery. However, thermal necrosis, loss of cutting precision and surface damage may occur in cutting process. The primary objective of this research is to improve cutting performance of bone by advantages of diamond wire sawing. Mechanism of material removal, cutting force, temperature and surface quality are analyzed based on experimental results. It is indicated that wire sawing provides small depth of cut, which is effective to obtain ductile material removal mode. Due to small material removal rate per abrasive, thermal energy is low and most of the heat can be taken away by the cyclic wire and bone chips. Consequently, cutting force and temperature in cutting zone are lower than that of traditional sawing. Due to the high efficiency of chip ejection, burrs and fracture are reduced and a significant improvement in surface quality is achieved. Based on cutting experiments with various values of cutting parameters, it is observed that better performance is achievable at higher wire speeds. These results provide a valuable basis for application of wire sawing and understanding of bone cutting mechanisms.     

正交车铣运动的矢量建模及表面粗糙度的理论分析

通过矢量分析,建立了正交车铣运动的矢量模型,并在此基础上给出了描述正交车铣运动的矢量表达式。建立了表面粗糙度的计算公式,并对它进行了简要的分析。     

微量润滑油润滑和冷风冷却加工法对高硅铝合金切削面的影响

由于高硅铝合金中含有大量硅结晶粒子,硬度较大的硅结晶粒子在切削中会加速刀具的磨损,所以,其被切削性非常不好。为解决这一问题,以往是使用大量切削油进行切削加工。但是,随着环境意识的提高,大量切削油的使用所造成的环境污染的问题不得不被认识并进行改变。使用对切削点进行微量植物性润滑油润滑和冷风冷却的方法进行研究,探讨对高硅铝合金切削面的影响。并因此探讨半干式切削加工的可行性。     

表面粗糙度模糊神经网络在线辨识模型

为解决零件加工中表面粗糙度在线检测困难这一问题,提出一种基于模糊神经网络的零件表面粗糙度在线辨识方法,并以外圆纵向磨削为例,建立表面粗糙度模糊神经网络在线辨识模型.首先研究前人建立的外圆纵向磨削零件表面粗糙度理论公式及经验公式,得出加工中的工件速度、砂轮速度、磨削深度和纵向进给量对零件表面粗糙度有直接影响,并进一步提出以在线测得的加工中工件与砂轮的速度比、磨削深度和纵向进给量作为零件表面粗糙度辨识模型的输入.由于加工过程极其复杂,无法建立加工中零件表面粗糙度与加工参数之间的精确数学模型,故将模糊神经网络引入建模过程中.同时,由于加工中零件表面粗糙度的对数与加工参数的对数存在线性关系,故模型中采用了T-S型模糊推理.此模型应用于实际磨削加工中,建模型精度可达97%,这进一步证明此在线辨识方法的可行性.     

STUDY ON COATING MECHANISM OF DIAMOND FILM ON CUTTING TOOL AND ITS APPLICATION

0 INTRODUCT[ONDiamond is a kind Of excellent cutting tool material for cutting non-fermus metal and nonmetallicmaterials. Because of the limited supply and high cost of natural diamond it has been mainly used forspecial aPPlications Where no other tools can Perform satisfactorily.The study of dePOsition of diamond film on cutting tools and its wide aPPlications began in 1980.Great Progress has been made at the same time. The [ypical principles used in coated-cutting tool are thehacrow…