高速走丝电火花线切割机床多次切割的实现

分析了高速走丝电火花线切割机床多次切割的条件及进行稳定多次切割需采取的措施,通过对机床机械结构及控制系统功能的改进与完善,采用洗涤性能良好的复合工作液,成功研制出具有稳定多次切割功能的商品化机床。第一次切割最高效率已超过200mm2/min,第四次切割后在平均切割效率大于50mm2/min的条件下,表面粗糙度Ra<0.8μm。     

电火花线切割高速走丝机床的断丝研究及对策

详细分析了高速走丝电火花线切割加工中的各种断丝原因,并分别根据不同原因提出了解决对策,可切实有效地减少断丝现象的发生,对工业生产中的实际应用具有很好的参考价值。     

高速走丝电火花线切割机床驱动系统结构设计

高速走丝电火花线切割机床的加工精度受机械传动精度影响很大.基于直线步进电机驱动系统的特性,本文提出了一种新型的高速走丝电火花线切割机床驱动结构.详细阐述了这种机床的关键零部件,并分析了结构设计的优点.     

高速走丝电火花线切割工作液失效研究

研究了高速走丝电火花线切割加工中切割效率、表面粗糙度、表面微观形貌的变化,指出采用切割效率作为工作液失效的表征更为直观和准确。比较了加工中复合工作液电导率、蚀除产物浓度、pH值、黏度与切割效率的变化关系,并从蚀除产物、浓度、电化学等方面分析了工作液电导率变化的原因,指出加工中电解作用产生的铁离子等对工作液电导率的上升起着主导作用,电导率与切割效率有很大的关联性,因此电导率可作为衡量复合工作液失效的指标。     

高速走丝电火花线切割机床可靠性研究现状与展望

文中对高速走丝电火花线切割机床的特点进行了介绍,并对其可靠性研究的重要性及迫切性进行了阐述.对目前高速走丝电火花线切割机床可靠性研究的状况进行了总结,并提出了其未来可靠性研究的方向、目标.根据国内外可靠性理论研究发展的趋势提出了可靠性研究与神经网络、模糊理论等前沿科学技术相结合的可靠性研究基本思路.     

高速走丝气中电火花线切割模具钢的研究

对高速走丝线切割机床进行了气中和液中的加工工艺对比分析。实验结果表明，采用气中切割加工工艺，可提高其加工工件的切割速度和表面质量。     

影响高速走丝电火花线切割丝损的因素与对策

分析了在高速走丝电火花线切割加工中出现的各种丝损现象，以及影响丝损现象的相关因素，提出了减少丝损的措施和对策，对进一步提高高速走丝电火花线切割的加工精度，减少电极丝的损耗．降低加工成本具有一定意义。     

电火花线切割走丝系统的创新研究

正电火花线切割机床的发展史20世纪60年代单向慢速走丝靠模电火花线切割机床进入我国。我们既惊奇其靠一根很细的黄铜丝,能在浸泡于煤油中的钢工件上加工出冷冲模的凹凸模块,同时又不满其极低的加工效果,每分钟只能加工几平方毫米。70年代初期,张维良高工发明了高速走丝机械系统,往复无限循环走丝,依然用的是靠模切割方式,但     

高速快走丝电火花线切割机床短循环方式的研究与应用

在总结实践和参考大量文献的基础上提出了用单片机实现往复循环走丝方法,利用控制电路对现有线割机床进行了改造。实践表明,该控制系统电路输出控制信号稳定;从实际效果上看,可显著提高工件表面质量。     

数控电火花线切割走丝路线的选择及优化

数控电火花线切割加工是实现工件尺寸加工的一种电加工技术,是模具加工的常用加工方法之一,对电火花线切割各项工艺指标中,影响加工质量因素很多,而加工路线的选择将直接影响零件变形的大小并影响加工精度.     

椭圆齿轮的CAD与线切割加工

利用图形交互方式进行椭圆齿轮齿形的计算机辅助设计,得到轮齿的标准渐开线齿廓,并对齿根处的过渡曲线进 行处理。以一个椭圆齿轮为例,进行设计和线切割加工,得到由图形所确定的齿轮轮廓。     

Cutting of polished single-crystal silicon by wire electrical discharge machining

Smoothly polished single-crystal silicon plates were cut by wire electrical discharge machining (WEDM) in water and in oil in order to investigate the effect of WEDM on the polished surfaces. For cutting in water, polished surfaces near cut sections have chips and cracks, and are extremely rough; the rough regions are upheaved. Examinations suggest that the upheaved region is silicon dioxide and results from oxidization of the surfaces by WEDM. Moreover, the polished surfaces far from the cut section are somewhat rough. For cutting in oil, polished surfaces near a cut section are smooth and almost flat although they have chips and cracks. These findings indicate the WEDM in oil is better than that in water for cutting polished single-crystal silicon to obtain high-quality surfaces.     

线切割加工工艺参数优化方法综述

线切割是一种非传统的材料加工方法,其主要的工艺参数有峰值电流、开路电压、脉冲宽度、脉冲间隔、伺服电压、丝速和丝的张力等,主要的工艺指标有材料去除率、表面质量、切缝宽度和白层厚度。综述了线切割工艺参数优化的研究方法,主要包括:人工神经网络、响应曲面法、田口法、灰色关联分析法和遗传算法。通过这些方法可以建立工艺参数和工艺指标之间的关系,从而发现影响工艺的重要参数,确定工艺参数的优化组合,预测基于优化参数的工艺指标。     

High-quality cutting of polished single-crystal silicon by wire electrical discharge machining

We discussed a method for cutting smoothly polished single-crystal silicon surfaces by wire electrical discharge machining to obtain a high-quality surface. To cut out parts with smooth surfaces from the plates by rough-cutting in water while maintaining the initial smoothness of the surfaces, several kinds of masks were applied to the polished surfaces before cutting. It was found that although the application of resin masks is effective for obtaining smooth surfaces far from the cut section, the surface smoothness near the section cut in water is less than in the case of cutting in oil. Next, finish-cutting in oil was performed to remove cracks and chips generated by rough-cutting in oil. As a result, although a few chips were generated at edges of the cut section, cracks were successfully removed by finish-cutting, so that the surface quality was successfully improved by finish-cutting in oil.     

Contouring of polished single-crystal silicon plates by wire electrical discharge machining

We investigate the effect of cutting by wire electrical discharge machining (WEDM) on the shape accuracy of polished single-crystal silicon. Single-crystal silicon plates are polished, and then contoured in deionized water or in oil by WEDM. The shape accuracy of the polished surfaces is measured with an interferometer. As a result, the polished surfaces are deformed into convex shapes by WEDM cutting. The polished surfaces tend to become flat as the roughness of the cut sections decreases, and the flatness is independent of the type of cutting liquid. Cutting in oil is advantageous for maintaining the smoothness of polished surfaces. These findings confirm that, in the contouring process of polished single-crystal silicon blocks, smooth and high-accuracy surfaces are achieved by conducting rough- and finish-cutting WEDM processes in oil.     

齿轮跑合的磨损机制研究

通过齿轮副跑合的模拟试验,得出齿轮副在跑合过程中磨损形式的转化规律。     

Measuring wear of the grinding wheel using machine vision

This paper proposes a new method for measuring grinding wheel contours using machine vision. The vision-aided measuring system comprises a CCD coupled with a telecentric lens, back lighting board and frame grabber. Measuring the image of the specimen with a grinded gap substitute directly captures the image of the actual grinding wheel. Using this method makes the 3 D of the topography of the grinding wheel into the 2 D of the contour of the grinding wheel. This method significantly simplifies grinding wheel wear measuring procedures compared with the traditional methods. Therefore, the presented paper provides a new method to improve efficiency and cost on measuring wear of the grinding wheel. The results show that this developed system achieves a repeatable accuracy of ±3 μm for the measurement of the grinding wheel contours.This paper has not been published elsewhere nor has it been submitted for publication elsewhere.     

Study on surface characteristics using phosphorous dielectric on wire electrical discharge machining of polycrystalline silicon

In this study, wire electrical discharge machining (WEDM) was implemented to process polycrystalline silicon ingot (electric resistance, 2–3 Ω cm), and the influences on surface characteristics were examined. At first, two different dielectrics, pure water and pure water with sodium pyrophosphate powder, were experimented to compare their effects on cutting speed and surface roughness. In the experiment, pure water with sodium pyrophosphate powder has shown that it enhanced process efficiency and improved surface smoothness. Then, the effects on cutting efficiency with different concentrations were examined; 0.05 M was chosen for its best performance. After setting the concentration, several experiments were conducted to find out how different currents and pulse-on times affect the cutting efficiency and surface roughness. The findings in this study prove that using phosphorous dielectric on WEDM could be applied onto polycrystalline silicon cutting. In addition, pure water with sodium pyrophosphate powder increases both working efficiency and improves infiltration of the phosphorous element on the surface. These findings could be future references on researches of solar cell in both industrial and academic fields.     

Thermal wear and electrical sliding wear behaviors of the polyimide modified polymer-matrix pantograph contact strip

In the present study, the polyimide resin (PI)/cashew-modified resin (YM) polymer-matrix pantograph contact strip (PMPCS) was prepared by using hot repressing, hydro-solidification and dipping treatment processes. The thermal properties of cured resins were studied by thermogravimetry analyzer and differential scanning calorimetry. The thermal wear and electrical sliding wear behaviors of PMPCS against copper were evaluated by a ring block wear tester at elevated temperature under dry sliding conditions and a wear tester which simulated the train motion under laboratory conditions, respectively. Worn surfaces and wear debris of PMPCS were analyzed by scanning electron microscopy and energy dispersive spectrometer, and the wear mechanism was discussed. It has been found that the thermal stability of the PI/YM is superior to that of the YM under the same testing conditions. The results also showed that PI/YM-PMPCS had superior wear resistance than that of YM-PMPCS at elevated temperature and with electrical current. At elevated temperature, the wear mechanism of tribological pair evolved from adhesive wear to oxidative wear with mild delamination wear. Arc erosion wear, oxidative wear, and adhesive wear were the dominant mechanisms of tribological pair during the electrical wearing process.     

A comparative study on the wear resistance of electrical discharge machined surfaces

The properties of the surface were affected by many factors such as the pulse parameters, tool electrode material, and dielectric liquid in electrical discharge machining. Austenitic, dual-phase, and ferritic steel work materials were electrical discharge machined using graphite and copper tool electrodes in hydrocarbon- based oil and water dielectric liquids. Then the surfaces were analyzed regarding sliding friction wear responses on a comparative basis. The results revealed that the surface wear responses are sensitive to the type of the tool electrode material when machining in water dielectric liquid. However, the use of hydrocarbon-based dielectric liquid substantiality suppresses the influence of tool electrode on surface wear response due to excessive carbon release from the cracked dielectric. The machined surface topographical features were also affected due to the used electrical parameters regarding crater size, globular attachments, and microcracks that led significant alterations in sliding friction response. Primarily, weakly bounded globular attachments on the machined surface were dislodged at the initial stages of the friction tests and led higher sliding distances to the steady friction conditions. Finally, the results were compared with the subsurface microstructural properties to comprehend the wear responses.