共查询到17条相似文献,搜索用时 78 毫秒
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为了研究旋转电极电火花沉积/堆焊的放电机理,文中进行单点间隙放电、单点接触放电和旋转电极连续放电试验,对放电过程中两极之间的电压和电流波形进行了采集和分析. 结果表明,在一定的电压和间隙条件下,电极与基体之间的介质能够被击穿出现间隙放电现象. 接触放电现象主要包括短路放电和间隙放电两个阶段. 旋转电极沉积/堆焊过程中电极与基体的接触状态复杂多变,放电过程中既存在非接触放电现象,也存在接触放电和短路放电现象,其中大部分是接触放电现象. 相似文献
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为了研究旋转电极接触力对电火花沉积放电过程参数和材料转移的影响,进行了不同接触力下的电火花自动沉积试验.分析了不同接触力下的各种放电波形的数量、放电脉冲的平均电压和电流等放电参数、电火花沉积的转移效率和沉积效率、沉积层的表面形貌和截面形貌、表面粗糙度等.结果表明,接触力的变化影响了旋转电极电火花自动沉积过程中各种放电类型的数量和比例.随着接触力的增大,接触放电比例逐渐减少而短路放电比例逐渐增加,放电脉冲的平均电压和平均功率逐渐下降而平均电流逐渐上升.接触力对电火花沉积的转移效率和沉积效率影响较大,对表面粗糙度影响不大.接触力为1~2 N时,自动沉积过程中的接触放电比例较高,转移效率和沉积效率也较高.在旋转电极电火花自动沉积过程,接触放电引起的材料转移量明显高于短路放电引起的材料转移量. 相似文献
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采用恒电流充放电法、交流阻抗法、循环伏安法研究了固液空间比对粘结式Ni(OH)2电极放电行为的影响,通过扫描电镜(SEM)观察了电极的表面形貌.结果表明:在单位面积活性物质载量一定的条件下,电极较厚,则活性物质颗粒之间的间隙较多;随着固液空间比的不断下降,Warburg扩散区的扩散速度加快,但电极的充电效率降低,放电容量减少,活性物质利用率减小,电荷转移电阻增大,填充密度增大到一定程度时,液相传质已经不容忽略. 相似文献
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揭示了电流条件下放电存在着状态转化,通道振荡等现象,讨论了这些现象与电极损耗的关系以及开路电压对放电通道稳定性的影响。 相似文献
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电沉积金刚石线锯制作工艺简单、沉积层与基体结合强度高,在超硬晶体切片加工领域具有广阔应用前景。基于电沉积技术的基本原理,分析电极材料沉积到基体表面并发生冶金结合的过程,设计制备金刚石线锯的装置:分析沉积方式和介质对沉积层的影响,确定旋转电极、气体介质的设计方案;用电极与基体间平均电压检测放电状态,据此调节电极与基体的距离,使电极处于电火花放电状态。以此装置电沉积线锯,发现:其运行可靠,可在φ0.4 mm不锈钢丝上沉积金刚石磨粒。 相似文献
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Debris concentration and bubble volume fraction in the bottom gap between the electrode and workpiece affect the state of consecutive-pulse discharge and the efficiency of electrical discharge machining (EDM). Thus, the mechanisms of debris and bubble movement during consecutive-pulse discharge should be elucidated. However, these mechanisms have not been fully understood because of debris and bubble movement in the machining gap are difficult to simulate and observe. This study proposes a three-dimensional model of flow field with liquid, gas, and solid phases for machining gap in EDM. The mechanisms of debris and bubble movement in the machining gap during consecutive-pulse discharge were analyzed through the model. Debris and bubble movement in consecutive-pulse discharge was observed through experiments. The results showed that the proposed simulation model is feasible. The bubble expansion is the main way that the bubbles exclude from machining gap. Much debris moves outside the machining gap following the excluded bubbles, which is the main way that the debris excludes from machining gap. The bubble expansion becomes strong with the increase of the discharge current and pulse-on time. 相似文献
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This paper describes the development of a pulse generator for nano EDM using a capacity coupling method. To obtain discharge craters of nanometer diameter, a pulse generator was coupled to the tool electrode by a capacitor. Since the influence of the stray capacitance in the electric feeders can be eliminated, the discharge energy can be minimized to accomplish nano EDM. This method also allows non-contact feeding of electric current to the rotating spindle, minimizing the run-out of the tool electrode. To control the gap width, the gap voltage was also measured using the capacity coupling method. 相似文献
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对不同叠加面积的纯铜板进行搭接电阻钎焊工艺试验和钎缝的超声波探伤、金相测试研究。结果表明:施加电极压力大小和施加压力的均匀性是钎合率达到要求和焊接质量稳定的关键因素,选用合适的电极压力可以使不同叠加面积的纯铜板电阻钎焊获得理想的钎合率。平均宽度小于78 μm的钎缝内部以局部焊缝间隙小形成的未熔合缺陷为主,平均宽度大于78 μm的钎缝内部以钎料未填满形成的"疏松"和圆形孔洞缺陷为主,超声波探伤与金相测试的钎合率大小相一致,可以采用超声波探伤对大面积叠加电阻钎焊的钎合率进行有效的检测。 相似文献
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High aspect ratio micro-hole drilling aided with ultrasonic vibration and planetary movement of electrode by micro-EDM 总被引:2,自引:0,他引:2
When a micro-hole is drilled deeply by EDM, the viscous resistance in the narrow discharge gap causes difficulty in the removal of debris and bubbles from the working area, leading to frequent occurrences of abnormal discharges and resulting in extensive electrode wear. This paper presents a new method of drilling high aspect ratio micro-holes by EDM, in which the planetary movement of an electrode, with enhancement from ultrasonic vibration, provides an unevenly distributed gap for the debris and bubbles to escape from the discharge zone easily. Micro-holes with aspect ratio of 29 have been drilled. 相似文献