基于开放式运动控制器的微细电火花加工控制技术研究

研究了基于开放式运动控制器UMAC的电火花加工控制技术。在微细电火花穿孔加工机床开发实例的基础上,介绍了相关的软硬件开发、轨迹自适应控制与接口设计等技术。应用表明,基于UMAC的电火花控制系统实现了与火花放电状态相适应的轨迹自适应控制,较好的满足微细电火花加工控制需求。     

超声波电机在三维微细电火花加工中的应用

论述了三维微细电火花加工系统的发展前景,搭建了一台微细电火花加工系统的原型样机.在该系统中,使用超声波电机做驱动装置,为微细电火花加工构造了可实现纳米级微量进给的运动平台,并进行了初步的平台定位精度检测.实验结果证明系统运行良好,运动平台能够达到很高的定位精度.课题在设计实用的精密微量进给机构的电机选择上,探索了新的方法.     

三维微细电火花加工伺服控制系统设计及实验研究

针对微细电火花加工伺服控制系统的要求,进行了微细电火花加工伺服控制系统总体设计.伺服控制系统特点是执行机构采用步进电机+压电陶瓷的宏微细合式驱动机构,实现了大行程和小步距的有机结合,能够提高电火花加工机床的加工性能.同时Z轴增加一个振动源,实现自动排屑和微调加工间隙.通过实验验证,证明系统运行良好,运动平台能够达到较高的精度,并实现了简单的极微细电火花加工.     

微细电火花三维成型加工控制系统的研究

构造了一个可实现纳米级微量进给的运动平台,并对该平台的控制技术进行了研究,提出了数字PID结合双向静差补偿策略.该补偿策略作为微细电火花加工控制系统的组成部分,大大提高了运动平台的运动精度.实验结果证明此系统运行良好,具有响应时间快、平稳超低速和超高分辨率的优点,达到了微细电火花加工的要求.     

微细电火花加工技术的研究进展

研究和综述了微细电火花加工技术的研究现状和发展趋势。比较分析了常用微细加工与微细电火花加工方法的特点及应用，论述了线电极电火花磨削技术的原理及在微细加工中的作用。结合电火花加工过程中无宏观作用力的特点，论述了微细电火花加工装置微小型化的可行性和几种主要形式。     

微细电火花加工机床关键技术

研制开发两台高精度、高性能,具有自主知识产权的微细电火花加工机床,并对微细电火花加工机床的几个特有关键技术进行了深入研究.基于压电陶瓷的宏微伺服进给系统能实现分辨率为3.42 nm的微进给,并且能实现振动式进给,以改善微细电火花加工的间隙状态,提高微细电火花的加工效率和加工质量.结合块电极反拷与线电极反拷的微细工具电极反拷系统,可高效高精度地现场制作微细电极,电极直径最小可达4 μm.基于多传感器信息融合技术的放电间隙状态监测技术,能很好地解决微细电火花加工间隙状态的监测与识别问题.RC脉冲电源不存在维持电压现象,这一最新发现为降低单脉冲放电能量难题提供一个新的解决途径,使得基于RC方法开发的超微能脉冲电源的单脉冲放电能量最小降至皮焦级,为微细电火花加工奠定了良好的基础.最后的微细电火花加工试验表明,所开发的微细电火花加工机床性能稳定,且加工质量良好,尤其适合加工孔径为50～200 μm的微细孔.     

基于DXF文件的压电自适应微细电火花二维CAM软件研究

微细电火花技术由于其微精密加工的特点,在航空航天和精密仪器制造领域发挥着重要的作用。然而,微细电火花加工的效率很低,因此提高微细电火花技术加工效率对其广泛应用有重要意义。文中介绍了实验室自主搭建的压电自适应微细电火花加工平台的结构及其工作原理。研究了基于DXF(Drawing Exchange Format)文件的二维CAM技术,解决了路径优化等关键问题,完成了二维CAM(Computer Aided Manufacturing)软件的开发,实现了二维代码的自动生成,并通过实验验证了其正确性。     

基于热学仿真的微细电火花加工表面形貌预测

根据热传导基本理论和微细电火花加工的实际情况,建立起微细电火花加工的热传播模型.采用ANSYS分析软件,基于有限元方法对P+硅和45钢两种材料单脉冲放电情况的温度场进行了数值模拟,分析了微细电火花铣削加工中表面粗糙度与放电能量之间的关系.结果表明,微细电火花仿真能够很好地模拟放电凹坑的温度场分布,进而预测加工表面形貌.     

压电自适应微细电火花加工系统特性分析

针对微细电火花加工过程中排屑困难,极易产生短路、拉弧等非正常加工现象,进而造成微细电火花加工效率低、电极损耗大等特点,基于压电陶瓷的逆压电效应提出了一种新的加工方法--压电自适应微细电火花加工技术,对其加工原理进行了详细阐述,并结合试验对该加工系统的加工特性进行了详细分析.试验证明该技术在加工过程中能够实现放电间隙与放电状态的自适应调节,促进捧屑,可有效控制短路及拉弧现象的出现,进而提高微细电火花的加工稳定性及加工效率,并能实现超低电压下的微细电火花加工.结合实例说明采用压电自适应微细电火花加工技术进行小孔加工的过程中能实现稳定加工,获得较高的加工效率,并且加工的小孔圆度较好,说明该技术在微小孔加工方面具有广阔的应用前景.     

电蚀产物对微细电火花电极形状损耗影响的实验研究

针对微细电火花加工技术特点,开展电极形状损耗形成机理的研究,设计了开放状态微细电火花加工实验方法,实现电蚀产物浓度的改变;通过实验对比不同加工状态下微细电火花加工电极形状损耗变化、工件表面微观形貌和重熔层情况,系统研究不同电蚀产物浓度作用下电极形状损耗的影响规律;分析微细电极形状损耗的影响机制,总结内凹坑形状变化与电蚀产物的内在关系。研究成果为实现微细电极的形状控制提供了一定的实验及理论依据,达到了提升微细电火花加工质量和加工稳定性的目标。     

Study on the nano-powder-mixed sinking and milling micro-EDM of WC-Co

Present study investigates the feasibility of improving surface characteristics in the micro-electric discharge machining (EDM) of cemented tungsten carbide (WC?CCo), a widely used die and mould material, using graphite nano-powder-mixed dielectric. In this context, a comparative analysis has been carried out on the performance of powder-mixed sinking and milling micro-EDM with view of obtaining smooth and defect-free surfaces. The surface characteristics of the machined carbide were studied in terms of surface topography, crater characteristics, average surface roughness (R _a) and peak-to-valley roughness (R _max). The effect of graphite powder concentration on the spark gap, material removal rate (MRR) and electrode wear ratio (EWR) were also discussed for both die-sinking and milling micro-EDM of WC?CCo. It has been observed that the presence of semi-conductive graphite nano-powders in the dielectric can significantly improve the surface finish, enhance the MRR and reduce the EWR. Both the surface topography and crater distribution were improved due to the increased spark gap and uniform discharging in powder-mixed micro-EDM. The added nano-powder can lower the breakdown strength and facilitate the ignition process thus improving the MRR. However, for a fixed powder material and particle size, all the performance parameters were found to vary significantly with powder concentration. Among the two processes, powder-mixed milling micro-EDM was found to provide smoother and defect-free surface compared to sinking micro-EDM. The lowest value of R _a (38?nm) and R _max (0.17???m) was achieved in powder-mixed milling micro-EDM at optimum concentration of 0.2?g/L and electrical setting of 60?V and stray capacitance.     

Improvement of machining characteristics of micro-EDM using transistor type isopulse generator and servo feed control

This paper describes the improvement of machining characteristics of micro electrical discharge machining (micro-EDM) using a newly developed transistor type isopulse generator and servo feed control. The RC generator is mainly applied in conventional micro-EDM even though the transistor type isopulse generator is generally more effective for obtaining higher removal rate, because the transistor type generator is unable to generate iso-duration discharge current pulses with small pulse duration (several dozen nano-seconds), which is the normal level for micro-EDM. A new transistor type isopulse generator was therefore developed using a current sensor with high frequency response. With the new transistor type isopulse generator developed, the pulse duration can be reduced to about 30 ns, which is equivalent to the pulse duration used in finishing by the conventional RC pulse generator for micro-EDM. In order to achieve stable machining and improve machining characteristics, a new servo feed control system for micro-EDM using average ignition delay time to monitor the gap distance was also developed. By integrating the transistor type isopulse generator with this new servo feed control system, we were able to obtain a removal rate of about 24 times higher than that of the conventional RC pulse generator with a constant feed rate in both semifinishing and finishing. The effectiveness of the servo feed control proved higher in finishing than in semifinishing, whereas the transistor type isopulse generator was more effective in semifinishing than in finishing.     

A two-stage servo feed controller of micro-EDM based on interval type-2 fuzzy logic

In order to improve the performance of micro-electrical discharge machining (micro-EDM), the most important issue is to develop a highly stable servo control system. In order to account for the characteristics of high frequency, serious signal distortion, and high noise in micro-EDM process, type-2 fuzzy logic sets are introduced which is able to handle these uncertainties effectively. Based on interval type-2 fuzzy sets theory, a two-stage servo feed controller is designed. The first stage of the controller is for detecting the discharge state for a single sample point, and the second stage is used to obtain the servo feed speed. In addition, the discrimination and statistical methods for discharge states of sample points are proposed to obtain the proportion of each discharge state in an analytical period. Experiments demonstrate that the new controller can obviously improve the processing efficiency of micro-EDM compared with traditional controllers. Therefore, the proposed interval type-2 fuzzy logic-based two-stage servo feed controller is an effective way to enhance the efficiency and stability of micro-EDM and meanwhile to achieve good processing quality.     

UMAC运动控制器在全自动打胶机上的应用

介绍UMAC在全自动打胶机中的应用,根据打胶机控制轴数多(共12轴)、联动轴数少的特点来组成基于UMAC运动控制器的全自动控制系统.UMAC的使用很好地解决了之前采用PMAC控制卡时对超过8轴后控制系统硬件配置上的一些不足,不但使硬件结构得到简化,而且提高了系统的稳定性、可靠性和扩展性.     

基于UMAC的自动钻铆机控制系统开发

选取UMAC控制平台,在IPC上实现控制系统开发.由于UMAC出色的开放性及稳定的控制性,并且可以支持多种语言开发,结合自动钻铆机的工艺流程,使用VC6.0和PCOMM32动态链接库开发控制软件,构建各个功能模块,实现机床控制.开发的自动钻铆机数控系统为开放式控制系统,用以满足自动钻铆机特殊的功能需要,以及为后续二次开发提供平台.     

基于UMAC的并联调姿平台手脉微调功能的开发

手脉微调作为自动装配定位系统不可或缺的功能,也是并联机构控制系统开发的难点之一。针对并联调姿平台的空间运动特点,提出了"手脉+IPC+UMAC"的硬件结构,通过研究并联机构的控制算法,以及手脉的控制原理,结合UMAC控制器的控制特点,利用VC++6.0开发了并联调姿平台的手轮微调模块。实际应用结果表明,该模块能够快速平稳的控制平台运动,该项技术对并联机构手轮功能的设计具有一定的参考价值。     

热喷涂技术的研究现状与发展趋势

热喷涂技术由于具有极大优势而被广泛的应用在工程领域中。主要讲述热喷涂技术的研究现状、发展趋势,包括主火焰喷涂技术、等离子喷涂技术、超音速火焰喷涂技术、电弧喷涂技术、超音速电弧喷涂技术以及冷喷涂技术等,并介绍这些热喷涂技术的研究发展与应用。     

微细电火花加工及其关键技术

综述了微细电火花加工的基本原理及最新研究进展。比较了LIGA技术与微细电火花加工的特点与应用。简要分析了微细电火花加工的关键技术：微细电极的在线制作、微进给装置、微小能量的脉冲电源、微小电极的运动轨迹规划、电极的损耗及补偿策略。展望了微细电火花加工在微三维结构加工中的应用前景。