氮化硅陶瓷轴承套圈滚道的高效高质量磨削试验研究

为提高氮化硅陶瓷圆柱滚子轴承套圈滚道的表面质量及磨削效率,使用超高速万能外圆磨床对套圈滚道进行高速磨削试验,分析了工件线速度、砂轮线速度和进给速度等磨削参数对套圈滚道磨削表面质量与磨削效率的影响机制与规律。试验结果表明,套圈滚道表面粗糙度随着工件线速度及砂轮线速度的增大呈先减小后增大的趋势,随着进给速度的增大而增大;当磨削速比为200时,随着砂轮线速度的增大,套圈滚道表面粗糙度变化不大,比磨除率增大,磨削效率提高;当砂轮线速度为150 m/s、工件线速度为0.75 m/s时,进给速度的增大使比磨除率增大,但套圈滚道表面质量变差;在试验条件下,套圈滚道高速磨削后表面粗糙度值在0.065 0～0.098 5μm范围内,满足精密加工要求。为提高磨削效率,推荐磨削速比为200、砂轮线速度为120～150 m/s和进给速度为18～28μm/min。     

磨削工艺参数对硬质合金刀具磨制损伤的影响

硬质合金刀具被广泛应用于航空航天、汽车、冶金等高端制造领域。硬质合金刀具的生产通常采用金刚石砂轮磨削加工,因此,砂轮的磨削工艺参数对刀具的成品质量有重要影响。本试验通过改变砂轮的线速度及进给速度加工硬质合金麻花钻,加工完成后,采用超景深显微镜、白光干涉仪和扫描电镜对钻头的磨削表面以及亚表面进行检测,分析砂轮进给速度及线速度对加工损伤的影响。结果表明：砂轮进给速度和线速度越大,锯齿量越大;当线速度与进给速度较小时,钻头的主切削刃易出现微崩刃现象;砂轮进给速度越大,钻头后刀面表面粗糙度越大;砂轮线速度越大,钻头后刀面表面粗糙度越小;钻头后刀面处的亚表面最大损伤深度随线速度的增大而减小;当线速度30m/s、进给速度160mm/min时,钻头的磨削损伤最小。     

基于粗糙度形成机理的曲面高速铣精加工参数选用

为在曲面精加工中获得理想的表面粗糙度,通过分析表面粗糙度的形成机理,建立了粗糙度与走刀行距、进给率关系的数学模型;通过实验,建立了高速曲面铣削时粗糙度与加工倾角、主运动线速度关系的图谱,实现了在生产过程中按照加工目标的表面粗糙度确定相应的走刀行距、进给率、加工倾角、主运动线速度等加工参数.研究结果表明,该研究对提高加工...     

基于正交实验的氧化锆陶瓷套圈内圆磨削研究

采用树脂结合剂金刚石砂轮磨削氧化锆陶瓷套圈内圆,分析了各磨削工艺参数包括砂轮的粒度、线速度(vs)、轴向振荡速(fa)和径向进给速度(fr)对氧化锆套圈内表面粗糙度的影响。利用正交实验,通过回归分析得到加工表面粗糙度的回归方程。实验结果表明,金刚石砂轮的粒度是对加工表面粗糙度影响最大的因素,随着砂轮粒度的减小,加工表面粗糙度呈明显下降的趋势,而砂轮的线速度、轴向振荡速和径向进给速度的变化对加工表面粗糙度的影响均不显著。     

电镀金刚石砂带磨削氧化铝陶瓷的试验研究

通过单因素试验分析了氧化铝陶瓷加工中工艺参数对磨削效率的影响;通过正交试验研究了试验因素对磨削效率的影响以及砂带结构参数对磨削表面粗糙度的影响,并确定合理工艺参数。结果表明,砂带线速度增加,磨削效率增加,砂带线速度过大,磨削效率下降;磨削效率随磨削压力的增加而提高,磨削压力增大到一定值以后,磨削效率明显下降;工件进给速度增加,磨削效率增加,进给速度增加到2.2mm/s以后,磨削效率下降较快。正交试验表明:工艺参数对磨削效率的影响大小为:磨削压力工件进给速度砂带线速度;磨削表面粗糙度随着砂带粒度号和植砂密度的增加而下降。     

氧化铝空心球砂带磨削钛合金的材料去除及表面质量研究

为了解决航空发动机钛合金叶片磨削加工中砂带使用寿命不足的问题,采用新型氧化铝空心球开展钛合金试样砂带磨削的相关工艺试验研究。通过单因素试验分析氧化铝空心球砂带加工钛合金板材中工艺参数对表面粗糙度和磨削比的影响,确定空心球砂带磨削钛合金参数的合理范围,进而通过正交试验研究磨削压力、磨削线速度、进给速度以及磨粒粒度等因素对表面粗糙度和磨削比的影响程度,确定空心球砂带磨削钛合金的最优工艺参数组合。     

超音速火焰喷涂WC涂层超高速磨削试验研究

针对超音速火焰喷涂碳化钨涂层存在的加工困难,研究了不同砂轮线速度对涂层磨削力、表面粗糙度及表面微观形貌的影响,试验结果表明,随着砂轮线速度的大幅度提高,涂层磨削力、表面粗糙度值都能得到明显的减小;通过观察磨削表面的微观形貌发现,在超高速磨削条件下,涂层材料的去除方式更多的以塑性去除为主.     

低速铣削中表面粗糙度影响因素及切削参数优化研究

通过铝合金薄壁工件切削试验,对铣削加工中表面粗糙度的影响机理进行分析,建立了铝合金薄壁工件表面粗糙度预测模型,采用多元回归正交分析法获得了表面粗糙度的经验公式。结合正交试验的极差分析,获取不同的加工参数对表面粗糙度的影响显著性。并基于表面粗糙度,以材料去除率为优化目标,对切削参数进行优化。研究结果表明,切削参数对表面粗糙度的影响显著性为:每齿进给切削宽度切削速度;较优化的切削参数为:切削速度201 m/min,每齿进给0.19 mm/齿,径向切宽11 mm。为铝合金工件的铣削加工提供理论方法和试验依据。     

基于正交试验的铝合金行切加工表面粗糙度研究

行切是航空结构件数控加工中的常用工艺方法,本文对铝合金航空结构件数控铣削过程中应用牛鼻铣刀行切加工零件表面特征的现象展开试验。针对不同切削线速度及每齿进给量对表面粗糙度的影响进行对比分析,试验结果显示,表面粗糙度不随理论残留高度的增加而增加,而是维持在一定范围;行距的增加并不会明显降低表面粗糙度;在该试验条件下优先选择较高的切削线速度及较低的每齿进给量能保证较好的表面粗糙度。     

AISI 1045钢窄深槽磨削表面完整性试验研究

采用直径为180mm单层电镀CBN砂轮在不同磨削参数下对AISI 1045钢进行高速缓进给窄深槽磨削试验,通过三维表面轮廓仪(SM-100)、维氏硬度计(HMV-G21ST)和金相显微镜(MM-4XCC)检测窄深槽侧面形貌、表面粗糙度、槽底硬度及金相组织等表面参数,分析了砂轮线速度、工件进给速度和窄深槽深度等磨削参数对表面完整性的影响.试验结果表明:随着工件进给速度的增大和窄深槽深度的增加,槽侧面粗糙度值增加,表面质量变差,且槽底硬度增大;砂轮线速度的增加有助于降低表面粗糙度值,提高表面质量;工件切入端与切出端,槽侧面磨痕较深,表面质量较差,中间区域具有较好的表面质量,同时由于温度的影响,与中间区域相比,切入端与切出端槽底硬度较低;槽底表面未出现组织转变,槽底亚表层发生塑性变形,晶粒细化且分布较为集中.     

Influence of ingot rocking on the surface quality of multi-wire sawing monocrystalline silicon wafers

This paper aims on slicing of monocrystalline silicon wafers using a newly developed diamond multi-wire reciprocating saw under ingot rocking process. A co     

Effect of reciprocating wire slurry sawing on surface quality and mechanical strength of as-cut solar silicon wafers

This paper investigates reciprocating wire slurry sawing for photovoltaic (PV) silicon wafering and compares the resulting wafer surface quality and its mechanical strength to that obtained in unidirectional wire sawing. It is found that wire reciprocation creates two significantly different morphological or cutting zones on the wafer surface. The zone width varies with the distance travelled by the wires, the cutting location on the wafer surface, and direction of wire motion. The size of the morphological zone created during forward motion of the wire is larger than that created during its backward motion. The zone width is found to decrease along the wire cut direction. In addition, there appears to be greater kerf loss and increased surface roughness in the forward cutting zone. In general, results suggest a higher material removal rate during forward motion of the wire than during backward motion. Notwithstanding the surface morphology variations, the fracture strengths of reciprocating wire sawn wafers are found to be quite similar to that exhibited by wafers produced by unidirectional wire sawing.     

Development of an electrolyte jet type apparatus for manufacturing electroplated diamond wires

Multi-wire sawing with a fixed diamond wire is widely used for the mass production of wafers. In this study, a novel electrolyte jet type electroplating method was devised to improve the productivity of these wires. The method is based on increasing the limiting current density (LCD) in the electroplating unit. First, an electrolyte jet type electroplating unit was designed, and the plating characteristics were investigated. To increase the LCD during plating process, the method of decreasing the depletion layer of nickel ions around the core wire was approached. The experimental results indicated that the LCD can be increased by increasing the flow rate of the electrolyte. Next, the influences of composite plating conditions on the state of abrasive distribution and density of the diamond wires were experimentally verified, and the process of selecting the optimal fabricating conditions was clarified. Lastly, the cutting performance of the prototype diamond wires was verified by slicing a polycrystalline silicon ingot. The relationship between the surface roughness of the sliced wafers and the abrasive density of the diamond wires was studied.     

Distribution of diamond grains in fixed abrasive wire sawing process

For over 20 years, wire sawing has been the primary method used for slicing ingots of silicon, sapphire, and silicon carbide into wafer substrates. Fixed diamond wire sawing has recently emerged as an alternative to slurry wire sawing as a means to shorten the time required for slicing and reduce the usage of slurry. The distribution of diamond grains on the wires strongly influences slicing performance in terms of material removal, surface topography, and subsurface damage. However, few studies have investigated this topic. This study established a model with which to simulate the distribution of diamond grains. Simulation results demonstrate that a higher density distribution reduces the rate of material removal because the loading is shared by the abrasives, thereby preventing the grains from penetrating deeply enough into the workpiece to facilitate the removal of material. Lower distribution density was shown to increase the loadings on the abrasives. These results demonstrate the importance of distribution density of diamond abrasives on the wire with regard to slicing performance.     

游离磨料线锯切割机改造与试验

游离磨料多线锯切割技术广泛应用于硅碇、水晶等材料的切片加工。为了方便研究游离磨料线锯的切割机理、切片工艺等,对电火花线切割设备进行改造,使其满足游离磨料线锯切割的要求。并采用准0.14 mm的钢丝线,对水晶材料（K9）进行切割实验,结果表明改造的切割设备满足切割实验需求,为后续的实验提供了基础保障。     

RESPONSE SURFACE ANALYSIS OF SLICING OF SILICON INGOTS WITH FOCUS ON PHOTOVOLTAIC APPLICATION

Polycrystalline silicon wafers are widely used in Photovoltaic (PV) industry as a base material for the solar cells. The existing silicon ingot slicing methods typically provide minimum wafer thickness of 300–350 μm and a surface finish of 3–5 μm R_a while incurring considerable kerf loss of 35–40%. Consequently, efficient dicing methods need to be developed, and in the quest for developing new processes for silicon ingot slicing, the wire-EDM (electric discharge machining) is emerging as a potential process. Slicing of a 3′′ square silicon ingot into wafers of 500 μm in thickness has been performed to study the process capability. This article analyzes the effect of processing parameters on the cutting process. The objective of the experimental study is improvement in slicing speed, minimization of kerf loss and surface roughness. A central composite design-based response surface methodology (RSM) has been used to study the slicing of polycrystalline silicon ingot via wire-EDM. A zinc-coated brass wire, 100 μm in diameter, has been used as an electrode in the slicing experiments. It has been observed that the optimal selection of the process parameters results in an increase of 40–50% in the slicing rate along with a 20% reduction in the kerf loss as compared to the conventional methods. The machined surfaces on the sliced wafer were free of micro-cracks and wire material contamination, thereby making it useful for electronic applications.     

单晶硅料摆辅助多金刚线切片的锯切力模型研究

料摆辅助多金刚线切片技术是实现硬脆材料高精高效加工行之有效的工艺技术,探明其工艺参数、锯切力和切片质量的定量关系,具有重要的现实意义。在研究金刚线运动轨迹的基础上,推导了考虑线弓影响的切割长度变化公式;结合压痕断裂力学和试验研究,建立并验证了料摆辅助切片的锯切力模型。开展了不同工艺参数对锯切力的影响分析,结果表明,料摆辅助加工可以降低锯切力近50%;摆动角度对最大切割力的影响较小,但摆角增大会加剧"锯齿形波动"周期内的锯切力极值幅度,摆动角速度对"锯齿形波动"的周期影响较大;在恒定进给速度条件下,进给速度越高,锯切力越大;在变速进给条件下,最大锯切力可降低12%左右。进一步进行了摆角分别为0°、3°、5°和7°的多金刚线切割单晶硅实验,试验表明,料摆辅助切片加工有助于减少硅片表面因脆性崩裂产生的表面材料破损、深凹坑等缺陷;相较于普通切片加工,在摆角5°工况时,工件的表面粗糙度和硬化层厚度最大分别降低30.1%和20.1%。     

Multi response optimization of wire EDM operations using robust design of experiments

In this present study a multi response optimization method using Taguchi’s robust design approach is proposed for wire electrical discharge machining (WEDM) operations. Experimentation was planned as per Taguchi’s L16 orthogonal array. Each experiment has been performed under different cutting conditions of pulse on time, wire tension, delay time, wire feed speed, and ignition current intensity. Three responses namely material removal rate, surface roughness, and wire wear ratio have been considered for each experiment. The machining parameters are optimized with the multi response characteristics of the material removal rate, surface roughness, and wire wear ratio. Multi response S/N (MRSN) ratio was applied to measure the performance characteristics deviating from the actual value. Analysis of variance (ANOVA) is employed to identify the level of importance of the machining parameters on the multiple performance characteristics considered. Finally experimental confirmation was carried out to identify the effectiveness of this proposed method. A good improvement was obtained.     

Study of EDM cutting of single crystal silicon carbide

Electrical discharge machining (EDM) is developing as a new alternative method for slicing single crystal silicon carbide (SiC) ingots into thin wafers. Aiming to improve the performance of EDM slicing of SiC wafers, the fundamental characteristics of EDM of SiC single crystal were experimentally investigated in this paper and compared to those of steel. Furthermore, EDM cutting of SiC ingot by utilizing copper foil electrodes was proposed and its performance was investigated. It is found that the EDM characteristics of SiC are very different from those of steel. The EDM machining rate of SiC is higher and the tool wear ratio is lower compared to those of steel, despite SiC having a higher thermal conductivity and melting point. Thermal cracks caused by the thermal shock of electrical discharges and the Joule heating effect due to the higher electrical resistivity are considered to be the main reasons for the higher material removal rate of SiC. It is concluded that the new EDM cutting method utilizing a foil electrode instead of a wire electrode has potential for slicing SiC wafers in the future.     

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.