外文翻译--电火花沉淀模的自适应控制系统

无锡职业技术学院毕业设计说明书 外文翻译 Although once considered a “nontraditional” machining process, EDM has been replacing drilling, milling, grinding and other traditional machining operations in many industries throughout the world. Since its early days as a “tap busting” method over 50 years ago, EDM has developed into one of the most advanced machining technologies. Todays EDM equipment uses advanced Computer Numerical Control (CNC) with up to six-axes simultaneous operation and state of-the-art power supply technology, which can produce a mirror surface finish and “split-tenth” accuracy. The tremendous advancements in EDM technology have been achieved through the collective efforts of many dedicated engineers employed by the major EDM builders and by researchers from some of the worlds leading institutions and research centers. This report provides an overview of the research studies and developments of these institutions and the activities of professional societies and other organizations throughout the world that are contributing to the continued advancements of Electrical Discharge Machining. Mechanisms of Technology Transfer Mechanisms of Technology Transfer According to the Federal Laboratories Consortium, there are several channels for bringing about the transfer of technology from government or private research centers to industry. The following list is a sample of the various mechanisms used 1. Cooperative research projects between industry and laboratories 2. Workshops, seminars, and briefings 3. Exclusive/non-exclusive licensing 4. Sponsored research where industry reimburses a lab for work done at the facility. 5. Consulting by lab personnel. 6. Employee exchange where researchers from the lab and industry trade assignments in areas of mutual interests. 无锡职业技术学院毕业设计说明书 7. Use of lab facilities where certain capabilities are not available at a particular company. 8. Laboratory visits to share information and discuss technical problems. 9. Publications and other printed literature. 10. Membership in industrial affiliate organizations that are associated with research labs. As defined in items 9 and 10, one of the objectives of EDM Technology Transfer (EDMTT) has been to provide a mechanism or source of gathering information from research centers with projects relating to EDM, and making this information available to anyone interested in the EDM process. One reference source published by EDMTT is the “EDM Technology” volume series, which contain EDM technical reports by universities, EDM manufacturers, or other technical research centers around the world. International and National EDM Conferences and Discussion Forums In an effort to establish a forum for the discussion of EDM research and developments, and help provide a course of instruction in basic and advanced EDM technology, several technical societies and other groups have established international or national conferences on EDM. Japan Japan Society of Electrical Machining Engineers(JSEME) Throughout its forty year history, the JSEME has been the predominant organization and driving force behind the research and development of EDM and the dissemination of this information in Japan. All of the major Japanese EDM builders and university EDM researchers present technical reports on the latest EDM research and developments at their annual conferences. At the JSEME “All Japan Conference” held in October 1994, thirty-five new EDM reports were presented, including the latest research by Mitsubishi, Sodick, Makino, Hitachi, and the leading research centers established at Japanese universities. The “Journal of the Japan Society of Electrical Machining Engineers” (Japanese language only) is their official publication which provides the latest technical information on the Japanese EDM industry. From a recent announcement by Professor Yasuo Kimoto, current President of JSEME, the Society will coordinate a new “International Journal of Electrical Machinin无锡职业技术学院毕业设计说明书 g” (IJEM). The aims of the IJEM are: 1) to propagate the latest scientific and technological news in the field of electrical machining methods, 2) to exchange experiences in putting electrical machining into practice, and 3) inform about the current state-ofthe-art and suggest directions of further development. IJEM editorial board members include representatives from Mitsubishi, Sodick, the leading Japanese research centers, and will also include members from outside Japan. U.S.A. Society of Manufacturing Engineers (SME) SME sponsors an annual EDM clinic and a fundamentals course. American Society of Mechanical Engineers (ASME) Starting in 1985, the Production Engineering Division of ASME began a session on nontraditional machining during their Winter Annual Meeting with EDM as the major topic of discussion. Modern Machine Shop/Gardner Management Beginning in 1989, Modern Machine Shop Magazine and Gardner Management Services has sponsored the largest EDM conference and exhibition in the United States. EDMTT has attended all of these conferences. National Institute of Standards & Technology (NIST) Organized under the U.S. Department of Commerce Technology Administration, NIST has held conferences on the “Machining of Advanced Materials” and presents technical information on using EDM. International Beginning in the sixties, the “International Institution for Production Engineering Research” has coordinated an international delegation of the worlds major EDM manufacturers and researchers for the “International Symposium for Electro-Machining” (ISEM). The International Institution for Production Engineering Research is also known officially as CIRP, which stands for “College International pour IEtude Scientifique des Techniques de Production Mechanique”. ISEM has been a forum of exchange for technical informationon EDM, Laser, ECM and other high-technology machining processes. ISEMXI will be eld in Switzerland and cover topics on EDM Process and Physics, EDM Machinery, EDM Technology, EDM Control and EDM Applications. 无锡职业技术学院毕业设计说明书 EDM Research and Development Centers Although EDM represents only a small portion of the total machine tool industry worldwide, the number of laboratories throughout the world performing EDM research and development studies has been growing steadily for several years. The more in-depth and well organized EDM research programs at various technical centers are funded by the major EDM builders or through government research grants. Several EDM manufacturers have also donated machines and supplies to universities with limited funds, which has helped to provide a program for future engineers to obtain a hands-on understanding of the capabilities of the EDM process. The following institutions have established research and development programs on EDM. They represent only a partial list of the laboratories and research projects throughout the world that contribute to the advancements in EDM technology. In addition to the work at advanced research laboratories setup by the major EDM manufacturers, the work performed at these institutions should have a direct impact on future developments in the EDM industry. U.S.A. Nontraditional Manufacturing Research Center, University of Nebraska-Lincoln Under the direction of Professor K. P. Rajurkar, this institution has established one of the worlds leading centers for academic studies and experimental research in EDM and other high technology machining processes. Courses taught in advanced manufacturing processes cover a broad range of topics and provide the student with an in depth study of EDM technology. Besides EDM, about 30 other advanced manufacturing processes are covered. The following graduate level course description provides a summary of these studies: Course Title: Advanced Manufacturing Processes (IE 970) Description: Advanced manufacturing processes provide an alternative (or sometimes the only alternative) for manufacturing complex shapes in a wide variety of materials. This course deals with topics ranging from the principles of operation, to the integration of these advanced processes into future flexible manufacturing systems. About thirty-one nontraditional manufacturing processes including Electrical Discharge Machining (EDM), 无锡职业技术学院毕业设计说明书 Electro-Chemical Machining (ECM), Laser Beam Machining (LBM), Abrasive Jet Machining (AJM), Electrochemical Arc Machining (ECAM), Electron Beam Welding, etc. are covered in this course. In the context of these advanced manufacturing processes, the following topics are covered. 1. Process Mechanism, Modeling and Simulation 2. Surface Integrity 3. Tool Design, CAD 4. Design of Related Machine Tools 5. Adaptive Control 6. Expert Systems, Neural Networks, Fuzzy Logic Applications 7. Integration within CIM Environment 8. Applications 9. Environmental and Safety Issues In addition to the class lectures, experimental projects on Die-Sinking EDM and Wire EDM are also required. The following list of projects provide an overview of past and future EDM research work conducted at the University of Nebraskas Nontraditional Manufacturing Research Center. Projects Conducted Over Past Two Years Effect of cryogenic treatment of electrode on EDM performance This project attempts to study the effect of cryogenic treatment of work and tool electrodes on EDM process performance. Cryogenic treatment of the work piece material and electrodes (for EDM and WEDM) was done by RPM Carbide, Inc. of Ohio. During cryogenic treatment, the material is cooled at 77 K for 24 hours and brought back to ambient temperature. Experiments on WEDM have been carried out using treated wire and untreated wire. It was experimentally found that the risk of wire rupture was reduced by 30% when using cryogenically treated wire. Experimental work on Die-sinking EDM and WEDM is continuing. Wire EDMing of Polycrystalline Diamond (PCD) An experimental study has been carried out to determine the effects of parameter settings in a state of the art WED machine on the machining performance. The WED无锡职业技术学院毕业设计说明书 M performance in cutting different layers of materials, such as PCD and WC, in the workpiece have been experimentally and theoretically determined. The mathematical model(s) of thermal stress for a theoretical explanation of the removal mechanism of diamond grain based on the numerical solution of Stefan problem is continuing. WEDM of Beryllium Copper Alloys The main objective of this project is to develop a database of optimal machine parameter settings for machining of Beryllium copper alloys of different heights during WEDM. This project is conducted with a Charmilles Robofil 100 WED machine. The relationships between the machine settings and machining characteristics such as machining speed, surface roughness, and overcut are determined experimentally. The machine setting parameters are charge frequency, charge current, pulse duration, capacitance, wire speed, wire tension and wire material. The optimization of parameter settings consists of two objectives, i.e. to maximize the machining speed and to maximize surface finish. A database of input parameters for both criteria is being developed. Study of discharge distributions in die-sinking EDM using divided electrode spark detection method The principal objective of this project is to study the influence of machining parameters (peak current and pulse on-time) and flushing methods on spark characteristics such as sparking efficiency and geometrical distribution of sparks in the machining gap. Peak current and pulse on-time change the machining conditions in the gap leading to changes in the sparking efficiency and spark distribution. A new method of spark detection system is employed to obtain the spark data. The solid tool is divided into number of smaller sections to identify each spark in different areas in the gap at different instants. This spark detection methodology can also be effectively used to find the efficiency of machining when subjected to different machining conditions. Adaptive control systems for die-sinking EDM The arc damage in the die-sinking EDM process reduces the machining productivity, decreases the machined surface quality, and increases the machining cost. The main objective of this project is to develop adaptive control systems for EDM to improve the process stability, avoid arc damage, and increase the machining rate. In this project, a digital EDM gap monitor was developed to precisely detect the time ratios of gap无锡职业技术学院毕业设计说明书 states including gap open, normal spark, transient arc, stable arc and short circuit. The unique feature of this system is the high frequency (HF) detecting technology that detects not only the occurrence of arc damage, but also the transient arc regarded as the forecasting signal of arc damage. The HF detection is the most reliable method in all EDM arc damage detecting technologies. A model reference adaptive control system and a self-tuning regulating system for EDM have been developed. These adaptive control systems detect gap state parameters through the EDM gap monitor and control the servo feed in real-time. The productivity with these control systems has been shown to be improved by 50% when machining under poor flush conditions. An EDM auto jumping controller using the PI self-tuning approach has also been developed on a state-of-the-art Mitsubishi K35 ED machine. This system adaptively adjusts the cycle time of the periodical retraction of the main spindle according to the detected EDM gap parameters. The arcing damage can be completely avoided, and the productivity is improved by 50% as compared to the manually set jumping cycle time. Advanced Wire-EDM control system In the WEDM process, wire rupture reduces the machining rate. This problem is caused by high power density along the wire, which is regarded as the ratio of sparking frequency to spark distribution length determined by the workpiece height. With most of the state-of-the-art WEDM equipment, the sparking frequency can not be on-line monitored and controlled, and an optimal pulse off-time to determine the sparking frequency for a given workpiece height is selected in accordance with manufacturer supplied database. The main objective of this project is to develop an advanced WEDM monitoring and control system that monitors on-line the change of workpiece height and control the spark frequency at optimal levels. A recently developed control system consists of a digital spark frequency monitor and a PC used as the main controller with an interface for power generator and servo system control. The PC monitors on-line the gap voltage, spark frequency, and the table feed rate to identify the workpiece height. This system regulates the table feed at optimal rates and adjusts the pulse off-time in real-time to control the spark frequency at optimal levels determined by the identified workpiece height. The spark frequency is always adjusted at a safe and highly productive level, and is able to follow the change in workpiece height to avoid wire rupture a无锡职业技术学院毕业设计说明书 nd to maintain an optimal cutting speed. The error of the workpiece height identification is 1 mm and the response of the identification to changes in workpiece height is 1 second. With this control system, procedures of NC programming and machine operations are simplified, and the machine operator does not need to input the workpiece height data into the machine and insert the power generator setting commands into the CNC program when cutting a multiple height workpiece. Future Projects at the University of Nebraska Abrasive assisted Electrical Discharge Grinding for machining advanced materials The machining rate with mechanical grinding of advanced materials, including electrically conductive ceramics, sintered carbides, and polycrystalline diamonds (PCD), is very low due to their high hardness and toughness. The EDM process provides an effective alternative to machine advanced materials. However, the surface quality generated by EDM is poor due to the recast layer and micro-cracks on the machined surface. The objective of this project is to develop an Electrical Discharge Grinding (EDG) process with an assistance of mechanical abrasive effects for improving the flushing condition and removing the damaged layer when machining advanced materials. During machining, the grinding electrode rotates in high speed, the spark discharges take place in the gap between the electrode and workpiece, and the machining gap is controlled by an EDM servo system. The preliminary experimental study indicates that the abrasive effect not only improves the surface quality of EDG, but also improve the gap flushing condition by effectively removing the eroded chips and particles, and providing higher normal spark ratio and better machining stability. Advanced on-line monitoring and control system for die-sinking EDM Graphite electrodes are popular for die-sinking EDM operations in U.S. industries because of higher machining rates and easy of fabrication. During EDM with graphite electrodes, the arc damage occurs frequently and is difficult to avoid. The main objective of this project is to develop an advanced monitoring and control system for die-sinking EDM when using graphite electrodes. In this project, an advanced and commercial available digital EDM monitor will be developed to detect the time ratios of gap states. The neural network technology will be used to analyze the gap voltage and curre无锡职业技术学院毕业设计说明书 nt signals and the data of gap states collected from the EDM monitoring system. A neural network and fuzzy logical identification system will be developed to predict the arc damage during the EDM process with graphite electrodes. An advanced control system will be developed to control on-line the discharge power, auto-jumping of tool electrode, and the servo system. EDM power generator for advanced materials When using EDM to machine the high thermal resistant materials including tungsten carbide, conductive ceramics, PCD and PCB, the discharge waveforms strongly influence the process performance. Most commercially available EDM power generators provide only square discharge current pulses. However, with square discharge pulses, the thermal energy can not be highly concentrated, therefore, the material removal rates for many advanced materials including tungsten carbide and conductive ceramics are very low. This project is proposed to developed an EDM pulse generator to provide particular discharge waveforms suitable to machine advanced materials. The prototype of the proposed pulse power generator will be developed to provide the transistor controlled RC pulse, multi-level waveforms with wider peak current and voltage ranges than current commercially available EDM power generators. A computer can program the discharge waveform and select different pulse parameters. The optimal waveforms for different material and machining requirements will be determined by the theoretical study of thermal modeling and analysis of the EDM process for advanced materials. University of California/Davis Research in several EDM fields, including (but not limited to) advanced EDM control systems aimed at increasing production and reducing operator attention and studies in wire breakage on WEDM. Texas A&M University EDM studies on difficult to machine materials such as tungsten carbide/cobalt composites, titanium diboride or other ceramic composite materials. 无锡职业技术学院毕业设计说明书 中文原文 一种新技术电火花的加工， 尽管电火花加工曾经被认为是非传统加工过程，但是电火花在世界范围内许多工业方面已经取代了钻孔、铣削、磨削和其它传统加工方法。尽管 50 年以前的早期它是 “tapbusting”的方式，但是电火花已经发展成为最先进加工技术之一。现代电火花加工设备运用先进的计算机数字控制，可达六轴同时工作和不同的电源技术。这些能够作为一面镜子高精度完成加工。 来自世界顶尖研究所和研究中心主要的电火花建设者和研究者雇佣的许多专业工程师通过共同努力实现了电火花技术的巨大先进性。这篇报道为学者、研究所的 发展、专职社会和世界范围内对电火花的先进性不断做出贡献的其它组织提供了研究纲要。 加工技术的转变 根据联邦实验协会调查，从政府、私人研究中心到工厂有许多带来技术转变的渠道。以下就是不同加工技术应用的抽样调查： 1.工业和实验室之间合作性研究项目。 2.车间、研究会和简报。 3.独家的 /非独家的许可。 4.工厂为工作设备设立实验室进行赞助性研究。 5.咨询实验室人员。 6.实验室和工厂贸易为了相互的利益，职员交换任务。 7.在一家具体的公司里，实验室设备使用能力不可获知。 8.实验室参观、分享信 息并讨论技术上的问题。 9.出版社和其他的印刷文献。 10.工业成员与那些和实验室相关的组织联合在一起。 如项目 9 和 10 所定义的 ,电火花技术转变 (EDMTT)的目的之一是从有关电火花项目的研究中心提供技术或信息源，而且使这些可得信息有利于电火花过程的任何一个环节。由电火花转变技术出版的一个参考信息是电火花技术专栏系列，它包括由大学、电火花制造业者和其它世界各地技术研究中心提供的电火花技术报道。 无锡职业技术学院毕业设计说明书 国际的和国内电火花参考和讨论论坛 为讨论电火花研究和发展建立一个论坛，并且为基本指导课程和先进的 电火花技术提供帮助，一些技术社团和其它组织已经建立了关于电火花的国际或国内参考。 日本 日本电力切割工程师社会（ JSEME） 尽管 JSEME 有四十年的历史，但在研究、发展和传播电火花以后，它在日本已经有了优越的组织和驱动力。日本所有主要的电火花建设者和大学的电火花研究员在电火花年度会议上将最近的电火花研究和发展，用技术报告呈现出来。在 JSEME， “所有的日本会议 ”于 1994 年十月召开，呈现了三十五个新的电火花报告 ,包括三菱、 Sodick、 Makino、日立的最新研究和日本大学建立的首要研究中心。 日本电力切割工程师团体的杂志是官方出版社，它提供关于日本电火花工业最新的技术信息。 教授 Yasuo 的一个最近公告指出， Kimoto ， JSEME 的现在总统 , 社会将会 调整为一个新的 “电力切割的国际杂志” (IJEM)。 IJEM 的目的是：1) 传播电力切割方法领域最新的科学和科技的新闻， 2）交换电力切割用于实践中的经验， 3）告知最近的状态和建议将来的发展方向。 IJEM 社论董事会成员包括从三菱、 Sodick 和日本首要研究中心的代表，也包括非日本人成员。 美国 制造业工程师的社会 (SME) SME 赞助一个年度电火花的临床讲义和一个基本课程。 机械工程师的美国社会 (ASME) 1985 年开始 , ASME的生产工程学在年度冬季会上，把电火花作为一个主要的讨论项目，召开了一个关于非传统加工的会议。 现代的机械工场 /贾德纳管理 1989 年开始 ,现代机械工厂杂志和贾德纳管理服务赞助了最近的电火花会议和在美国的展览会。 EDMTT 参加了所有的会议。 国内研究标准和技术 (NIST) 在商业的美国部门之下组织在美国贸易技术管理组织下 ,NIST 就 “先进材料的加工 ”问题举行了会议，并 列举了使用电火花的技术信息。 国际的 无锡职业技术学院毕业设计说明书 六十年代开始 ,“生产工程学研究的国际研究所 ”为 “电加工座谈会 ”（ ISEM）的国际代表团，即世界主要的电火花生产商和研究员进行了调整。生产工程学研究的国际研究所如 CIRP 一样正式地被大家接受 ,这代表了 “国际学院培养的IEtude 科技生产机械学 ”。 ISEM 已经是一个电火花、激光、 ECM 和其它高科技加工技术信息的交换论坛。 ISEMXI 将会在瑞士举行，它的主题范围包括电火花处理过程和物理学、电火花机械学、电火花科技、电火花控制和电火花应用。 EDM 研究和发展中心 虽 然电火花只是全世界工业总的加工工具的一小部分，但全世界范围内的关于电火花研究和发展的实验室在近几年内飞速增长。很多技术中心在主要的电火花建设者的集资下或通过政府研究部门的集资，越来越多的电火花研究项目得到更深入和更好的组织。一些电火花制造商为资金有限的大学捐赠了机器，这为将来的工程师获得亲自参与、理解电火花过程的能力提供了帮助。 下列机构已经建立了电火花研究和发展项目。他们只代表了全世界致力于电火花科学技术先进性的实验室的和研究工程的一部分。除了为主要的电火花制造商设立的先进研究实验事工作之外，也为那些对 电火花工业的将来发展有直接作用的研究所工作。 美国 非传统的制造业研究中心 ,内布拉斯加 -林肯大学 在教授 K. P. Rajurkar 的指导下，美国建立了一个研究所，它是全世界电火花和其它高科技加工的学术研究和实验领导中心。先进制造过程的课程的教学覆盖了一系列主题，为深入研究电火花技术的学生提供了帮助。除电火花技术之外 ,大约覆盖了 30 个其他的先进制造业加工过程。下列各项课程在一定水平上为这些研究提供一个摘要 : 课程名称 : 先进的制造业加工（ IE 970 ） 描述 : 先进的制造业加工为多种材料制造 复杂的形状提供另一选择（或有时称为替代选择）。这课程能够处理从基本操作到将这些先进过程整合为一个复杂的制造系统。包括电火花加工（ EDM）、电化学加工（ ECM）、激光加工（ LBM）、磨料喷射加工（ AJM）、电化学电弧加工（ ECAM）、电子束焊接等等，这个课程大约覆盖有三十一个非传统制造加工。在先进制造加工的文章中，覆盖了以下主题： 1.机械装置加工，靠模切和模拟 无锡职业技术学院毕业设计说明书 2.表面轮廓 3.工具设计 ,电脑辅助设计 4.加工工具相关的设计 5.适当的控制 6.专家系统，神经网络 ,模糊逻辑应用 7.CIM 环境整合 8.应用 9.环境的和安全问题 除了课程之外 ,也需要电火花沉淀和电火花线切割实验项目。 以下所列清单项目为内布拉斯加的大学非传统加工研究中心的过去和将来的电火花研究工作提供了一个纲要。 过去两年计划 电火花运行时，电极的低温处理的效果 这个计划尝试研究电火花运行时，工具电极的低温处理效果。在俄亥俄州的公司，工件材料和电极的低温处理是由 PRM 碳化物完成的。在低温处理时候，材料在 77K 温度 24 小时冷却到周围环境的温度。已经完成了正确对待已处理的金属线和未处理的金属线的 WEDM 实验。实验时发现，低温处理金属线，使金属线破坏的危险性减小了 30%。关于电火花沉淀和 WEDM 的实验性工作一直在继续。 复晶体金刚石的电火花线切割 (PCD) 已经实行的一项实验性研究决定了 WED 加工过程在运行时参数设置的效果。 WEDM 运转在切削材料的不同层面时，在工作件中，像 PCD 和 WC 这样的材料 ,是由实验和理论共同决定的。热应力的数学模型一