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。     

模具生产联合体加工作业统一调度问题的研究

模具生产联合体是由小规模企业组成的模具设计、制造联盟，由于设备、工装和人员分属于不同的加盟企业，其作业排序过程非常复杂。为此提出一种复合式模具生产联合体的生产排序方法：依据基本优先规则首先完成单一工序作业，然后对多工序作业用改进遗传算法进行工艺优化，求出最优解和次优解，再使用评价函数法选择最佳作业路线。该方法在生产试验中取得了良好的成效．能较好满足模具用户和加盟企业两方面的需要。     

Machining characteristics and fracture morphologies in a copper-beryllium (Cu-2Be) alloy

The technology of materials removal is improved greatly by the introduction of advanced cutting tools like cubic boron nitride, ceramics, polycrystalline diamond and the more recent whisker-reinforced materials. In this paper, the influence of cutting temperature on machinability, mechanical properties, microstructure, and fracture morphology of Cu-2Be alloy using a polycrystalline diamond cutter is investigated. The information on machining, microstructure, and fracture morphology of Cu-2Be alloy are very useful to understand their fabrication characteristics and the basic mechanisms of its deformation and fracture. The machinability (in terms of surface finish) of Cu-2Be alloy is evaluated as a function of cutting temperature, resulting from wet and dry cutting. Machining is carried out on a Hardinge Cobra 42 CNC machine (Hardinge Inc., Elmira, NY), and the machining parameters used—cutting speed, depth of cut, and feed rate—are kept constant during both wet and dry cutting. The machined surface finish on Cu-2Be alloy is measured using a surface finish analyzer (Surftest 401, series 178) technique. The machined specimens are examined for their strength and hardness properties using a standard Universal Testing Machine and Rockwell hardness tester, respectively. Wet cutting (using coolants) produced a smooth surface finish when compared with dry cutting of the Cu-2Be alloy. The machined specimens are examined for their microstructural features using a Nikon optical microscope. The specimens are etched using a suitable etchant solution for revealing such microstructure constituents as grain size, phase proportions, and the possible overheated areas (especially in dry cutting). The fractured surfaces from the tensile and impact toughness tests are investigated for their fracture morphologies (dry and wet cutting) using a microprocessor-controlled scanning electron microscope (Jeol Model JSM 5910 LV). A detailed analysis is also made to understand and interpret the basic fracture mechanisms responsible for crack initiation and crack propagation. The Cu-2Be alloy showed relatively higher mechanical properties in wet cutting in comparison to dry cutting operations. Fracture studies demonstrated intergranular and ductile fractures as dominant modes of fracture mechanisms in Cu-2Be alloy.     

Leaded brass rods C 38500 for automatic machining operations: A technical report

C 38500 is a widely used copper alloy with a great variety of applications from decoration and architecture to mechanical/electrical engineering. The chemical composition of this alloy offers superior machinability and subsequently increased productivity in high-speed machining and manufacturing processes. In European countries, this alloy is used primarily as free cutting brass (CW 614N according to EN 12164: 1998), similar to C 36000 alloy, which is used also for thread rolling. The lower percentage of Cu compared to C 36000 (nominal 58% instead of 61%) decreases the cost of the raw materials. This paper reports the principal aspects of microstructure, mechanical properties, and machinability of this alloy in relation to the industrial manufacturing process used.     

制作微器件的超声电解复合微细加工基础研究

提出一种制造MEMS微器件的新技术——超声电解复合微细加工；设计微细加工工艺系统，进行一系列微细加工基础工艺试验，验证超声电解复合微细加工在微器件制造中的可行性．展示了该技术在提高微细加工精度、效率、表面质量等方面的优势，研究成果对完善MEMS器件制作技术具有重要理论意义与实用价值。     

多体系统理论在数控加工精度软件预测中的应用

基于多体系统理论和虚拟加工技术的基本原理,阐述了多体系统的特征矩阵,研究了数控机床刀具成形函数和空间误差模型,提出和分析了机床加工精度软件预测的建模方法,最后为了验证所述精度预测方法的有效性,进行了软件预测和实体加工的加工精度比较实验.     

磁粒研磨光整加工的实验研究

通过实验对磁粒光整加工中的关键部件——磁极的形状做了较全面的分析，得到了适合磁粒研磨的最佳磁极形状，解决了在磁粒研磨中经常出现的“磁滞”现象，从而提高了加工效率，改善了工件质量，同时也延长了磁极的使用寿命，为磁粒研磨技术在生产中的应用提供了重要的理论依据。     

Examination of wire electrical discharge machining of Al2O3p/6061Al composites

Alumina particle reinforced 6061 aluminum matrix composites (Al₂O₃p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al₂O₃p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al₂O₃p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking.The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al₂O₃ particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al₂O₃p/6061Al composite are easily formed, basically due to some embedded reinforcing Al₂O₃ particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al₂O₃p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness.     

数控车床碰撞检测系统中NC程序检错与纠错模块的开发

讨论了对NC程序进行检错的意义，提出了数控车床碰撞检测系统的总体结构，包括机床、夹具等加工环境。以及与CAD软件的集成模块。介绍了NC程序的特点，并在VC6．0环境下开发了NC程序检错与纠错模块．通过设计数据结构解决了碰撞检查过程中工件不断变化的难题，为进一步具体研究奠定了基础。     

锻件尺寸的设计

提出锻件尺寸的设计不应仅以零件图为基础，而应考虑加工工艺，尤其是加工时选用的粗基准，指出合理的设计锻件尺寸不但可保证锻件各面有均匀合理的粗加工余量，而且可保证非加工面与加工面之间的位置及尺寸。