后混合磨料水射流切割工程陶瓷的特性分析

对后混合磨料水射流切割工程陶瓷的特性进行了理论和实验分析，探讨了磨料水射流切割工程陶瓷切割机理，分析了改变切割工艺参数对切割深度的影响特性。     

磨料水射流切割工程陶瓷的机理及实验分析

通过对磨料水射流切割机理及形貌分析,从理论上探讨了磨料水射流形成的液固两相射流是具有一定冲蚀动能的冷态单点动能能源,可对工程陶瓷材料进行冲蚀切割,并发现磨料水射流冲蚀材料的破坏主要是由气蚀破坏、磨料水射流的冲击作用,磨料水的动压作用以及引起的疲劳破坏和水楔作用所致.利用高压磨料水射流切割设备对工程陶瓷进行切割实验,分别对三氧化二铝、碳化硼、碳化硅等工程陶瓷材料进行切割,分析了压力、喷嘴横移速度、靶距等切割参数对其切深的影响.结果表明:磨料经冲蚀工程陶瓷以后,如石榴石磨料经冲蚀作用之后,可重复利用价值很小.     

金刚石工具钻削加工工程陶瓷孔的实验研究

金刚石工具钻削加工工程陶瓷孔时的材料去除率随着工具转速、磨粒直径以及外载荷的增大而增大；随着材料自身硬度和断裂韧性的升高而降低。本篇实验研究了各主要加工参数与材料去除率及孔加工质量的关系。1实验条件1．1实验设备和工件材料实验设备是利用CA6140车床改装而成的。工具使用专用夹具装夹后，利用三爪卡盘装夹于机床的主轴上。工件材料选用99．5％的Al2O3工程陶瓷。1．2金刚石工具的选择1．2．1金刚石磨料粒度的选择金刚石工具中金刚石磨料的粒度直接影响工程陶瓷材料的加工表面质量和加工效率。通常磨料粒度越粗，加工效率越高…     

新型复合式激光水射流切割氧化铝陶瓷实验方法研究

针对陶瓷材料传统加工方式,如激光空冷加工、磨料水射流技术以及金刚石切割等具有加工精度较差、材料去除率低以及刀具磨损严重等问题,研究了一种新型激光水射流切割方式,全新的复合式激光与水射流共同作用下,利用激光加热和水射流快速冷却所产生的大量热应力对硬脆氧化铝陶瓷材料产生热断裂,切开陶瓷。结果表明,激光水射流切割硬脆氧化铝材料相比于激光空气冷却切割和其他传统切割方式具有材料切口小,材料去除量较小以及切割后材料表面精度高。     

旋转超声波加工中延性去除模式的实验研究

介绍了工程陶瓷旋转超声波加工中延性去除模式的存在条件及材料去除机理，通过实验分析了各种加工参数对材料去除率的影响。实验结果表明，适当增加转速、降低静压力、相应地减小磨料粒度，有利于实现工程陶瓷材料去除机理由脆性去除向延性去除转变。在延性去除模式下，磨料粒度、静压力、转速和振幅的增加均导致材料去除率的增加。     

基于混合策略的磨料水射流切割工艺参数的优化

提出了一种模糊逻辑理论与遗传算法相结合的混合方法,该方法可以优化在给定材料厚度的条件下,磨料水射流切割各种材料的工艺参数。本文以理论为基础,应用实验数据建立了模糊控制模型。这个特殊的模糊控制模型可以预测在任何给定一组加工参数时,可获得的切割深度。遗传算法结合模糊模型可以自动确定磨料水射流切割各种材料时的最佳参数组合。通过对磨料水射流切割黑色花岗岩这一实例的研究,验证了该混合方法是有效的。     

金刚石压齿锯片在先进陶瓷加工中的应用评价

针对先进陶瓷材料的切割加工中存在着切割效率低、工具磨损快等问题,本文通过用金刚石压齿锯片加工氧化铝陶瓷的实验,研究锯片的磨损失效机制,探讨高效低成本的先进陶瓷切割技术.实验中用金刚石压齿锯片在不同加工条件下对氧化铝陶瓷材料和玉石进行切割加工,测量切割法向力和切向力,并跟踪锯片刃口形貌的变化及其磨损过程.实验结果表明,由于材料性质的差异,氧化铝陶瓷的切割力和力比均要明显大于玉石.锯片的磨损是由于该类型锯片的刃口上金刚石磨料浓度太低,而且结合剂的把持力不足导致金刚石大量脱落而失效的,并造成金属基体与工件间的摩擦加剧,切割比能也相应增加.     

工程陶瓷的等离子弧切割实验研究

在分析采用激光、磨料水射流、电火花线切割等方法切割工程陶瓷技术的现状与特点的基础上,提出采用附加阳极等离子弧切割工程陶瓷的基本思想,通过实验证明上述方法可行且具有独特的优点。     

高压水磨料射流切割的力学特性与模型

通过理论分析与实验测定，分析和建立了高压水磨料射流切割的力学特性与模型，得出水射流的流量系数为０．７５，磨料射流的平均流速系数为０．９５。认为水射流主要通过水介质的滞止动压进行切割，磨料射流主要通过磨粒的冲击动压进行切割。给出了射流切断面积速度与材料破坏能量的关系曲线。     

高压水磨料射流切割的力学特性与模型

通过理论分析与实验测定，分析和建立了高压水磨料射流切割的力学特性与模型，得到水射流的流量系数为０．７５，磨料射流的平均流速系数为０．９５。认为水射流主要通过水介质的滞止动压进行切割，磨料射流主要通过磨粒的冲击动压进行切割。给出了射流切断面积速度与材料破坏能量的关系曲线。     

On the mechanism and mechanics of material removal in ultrasonic machining

Precision abrasive machining processes such as ultrasonic machining are commonly employed to machine glasses, single crystals and ceramic materials for various industrial applications. Until now, precision machining of hard and brittle materials are poorly investigated from the fundamental and applied point of views. Taking into account the major technological importance of this subject to the production of functional and structural components used in high performance systems, it is often desired to estimate the machining rate for productivity while maintaining the desired surface integrity. The success of this approach, however, requires not only the fundamental understanding of the material removal on the microstructural scale but also the relationship between the machining characteristics and material removal rate in ultrasonic machining. In this study, the ultrasonic machining of glass was investigated with respect to mechanism of material removal and material removal rate (with basic machining parameters) with a mild steel tool using boron carbide abrasive in water as slurry. The analysis indicates that the material removal was primarily due to the micro-brittle fracture caused on the surface of the workpiece. For micro-brittle fracture mode, the relationship for the material removal rate, considering direct impact of abrasive grains on the workpiece, based on a simple fracture mechanics analysis has been established. The effect of machining conditions on material removal rate has been discussed. This research provides valuable insights into the material removal mechanism and the dependence of material removal rate on machining conditions and mechanical properties of workpiece material in ultrasonic machining.     

工程陶瓷圆弧成形磨削力预测与实验研究

圆弧成形磨削是难加工零件复杂型面的加工方法,对其磨削力的研究有利于改善工程陶瓷的表面质量。基于圆弧砂轮的结构特点及尺寸趋近思想对陶瓷材料圆弧成形磨削力进行预测。通过研究磨粒对工程陶瓷的去除机制,提出建立单颗磨粒滑擦、塑性及脆性去除磨削力模型。基于砂轮磨粒尺寸与分布差异,利用概率统计方法对磨削中不同去除方式的有效磨粒数进行探讨,进而实现圆弧成形磨削力理论模型的构建。最后通过磨削力实验对理论模型进行验证。结果表明：法向磨削力和切向磨削力理论值与实验值平均误差分别为8.793%和9.986%;磨削力随着磨削深度及进给速度的增加而增加,随着砂轮速度的增加而减小。     

面向工程陶瓷的单颗金刚石磨粒划擦磨损规律

为了研究工程陶瓷平面磨削中金刚石砂轮的磨粒磨损规律,制备圆锥形单颗粒金刚石磨具模拟实际磨粒切削刃。以金刚石磨粒的尖端圆弧半径表征磨粒切削刃锋利程度与磨削能力,并用圆弧半径的磨损规律等效描述切削刃磨损特性。采用基于扫描电镜与数据拟合的技术测量单颗磨粒金刚石尖端圆弧半径。运用单因素试验及正交试验分析了金刚石颗粒尖端形状、材料种类与加工参数对磨粒磨损规律的影响。实验结果表明,当顶锥角2θ为120°、磨削深度ap0.01 mm时,金刚石磨粒具有较高划擦寿命。各因素的影响主次顺序为:顶锥角>磨削深度>工作台速度。本研究为金刚石砂轮磨粒规格和磨削用量的选取提供了重要参考。     

基于遗传算法的工程陶瓷电火花加工技术

工程陶瓷材料硬脆、导电率低,难以获得高效精密的电加工效果.本文针对工程陶瓷电火花加工特点,在分析国内外工程陶瓷电火花加工技术的基础上,提出了基于遗传算法的工程陶瓷电火花加工方法.该方法结合遗传算法、神经网络及模糊控制理论构造了多环式自适应控制系统,在线对加工过程进行断丝预防、加工工艺自适应和加工参数自适应监测与控制,从而为难加工材料实现高效精密的电火花加工提供理论与技术指导.     

Grinding characteristics,material removal and damage formation mechanisms in high removal rate grinding of silicon carbide

Development of advanced ceramics such as silicon carbide has gained significant importance because of their desirable properties. However, their engineering applications are still limited owing to the limitations in developing damage-free and economical machining techniques. It is often desired to increase the machining rate to improve productivity while maintaining the desired surface integrity. The success of this approach, however, requires a fundamental understanding of the material removal and damage formation mechanism in grinding. In this paper, high removal rate grinding of silicon carbide was investigated with respect to material removal and basic grinding parameters using a diamond grinding wheel. The results showed that the material removal was primarily due to the microfracture and grain dislodgement under the grinding conditioned selected. For grain dislodgement removal mode, the relationship for the removal rate in scratching based on a simple fracture mechanics analysis has been established. This research provides valuable insights into the surface and subsurface integrity and material removal mechanism during high removal rate grinding of silicon carbide.     

陶瓷磨削的材料去除机理

磨削是目前工程陶瓷的主要加工方法,为了开发新的高效、低成本、低损伤加工陶瓷的方法,需要更深入地揭示其加工机理。本文介绍了陶瓷磨削的材料去除机理方法的研究进展,就其进行了一定的讨论,并得出相关的结论。     

Fixed abrasive diamond wire machining—part I: process monitoring and wire tension force

The process monitoring and mechanics of fixed abrasive diamond wire saw machining are investigated in this study. New techniques to affix diamond particles to a steel wire core have advanced to make this process feasible for the machining of ceramics, wood, and foam materials. Developments in fixed abrasive diamond wire machining are first reviewed. Advantages of using fixed abrasive diamond wire machining are then introduced. The process monitoring and signal processing techniques for measuring the cutting forces, wire speed, down feed rate, and wire bow angle in diamond wire saw machining are developed. The application of a capacitance sensor to measure the wire bow and a procedure to convert the wire bow to vertical cutting force in a rocking motion wire saw machine are developed. The tension force of the wire during cutting is also derived and discussed.     

Experimental investigation of surface/subsurface damage formation and material removal mechanisms in SiC grinding

The difficulty and cost involved in the abrasive machining of hard and brittle ceramics are among the major impediments to the widespread use of advanced ceramics in industries these days. It is often desired to increase the machining rate while maintaining the desired surface integrity. The success of this approach, however, relies in the understanding of mechanism of material removal on the microstructural scale and the relationship between the grinding characteristics and formation of surface/subsurface machining-induced damage. In this paper, grinding characteristics, surface integrity and material removal mechanisms of SiC ground with diamond wheel on surface grinding machine have been investigated. The surface and subsurface damages have been studied with scanning electron microscope (SEM). The effects of grinding conditions on surface/subsurface damage have been discussed. This research links the surface roughness, surface and subsurface damages to grinding parameters and provides valuable insights into the material removal mechanism and the dependence of grinding-induced damage on grinding conditions.     

基于虚拟仪器的精密加工测试系统

文章提出了一种基于虚拟仪器技术的精密加工测试系统，并讨论了这种测试系统的原理以及硬件和软件的实现。本测试系统采用美国NI公司的PCI-6024E数据采集卡，在LabVIEW编程环境下，实现了对信号的数据采集、显示及数据处理，并成功应用于磨料水射流复合电解加工系统的测试。