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慢走丝线切割机床走丝系统的开发与研究
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指导教师：e
[摘要]本论文是针对慢走丝线切割机床走丝系统的开发与研究而进行研究的，对于慢
走丝线切割机床来说，走丝系统的重要性已经不言而喻了，因为线切割机床的工作是基于电极丝而进行的，而走丝系统则是控制电极丝的张力，走丝速度的。走丝系统的好坏决定了线切割机床的加工精度和加工质量，可以说，走丝系统就是线切割机床的检测表，体现了线切割机床的水平以及质量。而近几年来随着民用工业和军用工业的发展，对于工件的加工精度和表面质量的要求也越来越高，随着细微化，高精度的发展趋势，现有的慢走丝线切割机床已经越来越难以满足加工需求，所以，对于线切割机床的核心——走丝系统的开发与研究也就变得势在必行了，也使的这个研究具有了非凡的意义。
本文是针对低速走丝线切割机床开发而进行研究的，通过查阅了大量国内外有关电火花线切割机床的资料和文献，对现阶段慢走丝线切割机床的发展趋势进行分析，总结了国内外慢走丝线切割机床走丝系统中对于恒张力控制和恒丝速控制的发展和应用现状，对各种恒张力，恒丝速控制其进行了分析。在这些的基础上建立以PC机为控制系统主控单元，以运动控制卡和D/A输出卡功能模块为转换输入输出，以步进电机为丝速控制执行元件，磁粉制动器为张力控制执行元件的张力控制系统；分析了走丝控制系统中主要元件的工作原理。
根据以上的基础理论对慢走丝线切割机床走丝系统进行设计与研究。 [关键词]慢走丝线切割机床; 走丝系统; 恒速恒张力控制
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The Develop And Research WEDM-LS wire feed system
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Tutor : ee
Abstract： This article is mainly research about the wire-feeding system of WEDM-LS, about WEDM-LS, the wire-feeding system is very important, because every part of the wire feed system has reflected the level and quality of the machine tool, and the wire-feeding system is control the tension and wire-speed of wire. The quality of wire-feeding influence the surface quality of processing work piece directly, one word, the wire-feeding reflect the quality of WEDM-LS, show us the level and quality of WEDM-LS. These years with the development of civil industrial and military industrial, the requirements is increasingly of workpiece about the machining accuracy and surface quality, with the developing of micro and high precise manufacture, existing WEDM-LS increasingly difficult to fulfill processing needs, so for the core of WEDM-LS—the develop and research of wire-feeding become very important.，also make this research has a different means.
The article is mainly about the research according to the development of WEDM-LS, in this paper on basis of a lot of domestic and overseas technique literature on WEDM-LS, analysis about the tend of WEDM-LS，summarized the development and application of the constant tension control for electrode wire of the WEDM-LS, analysis the control of the constant tension and constant speed. Basis on these set a wire-feeding system is researched with pc as main controlling unit, use the kinetic control card and D/A output card as converting I/O, the stop motor as the wire feeding motor,, the magnetic powder brake as performing device,; The working model of main part of the wire-feeding system are analyzed.
Basis on these theories to develop and research the WEDM-LS.
Key Words: WEDM-LS;Wire-feeding system; constant speed and constant tension
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目 录
1 绪论.......................................................1
1.1 引言.......................................................1 1.2慢走丝线切割机床简介.......................................1 1.3国内外慢走丝线切割技术研究概况.............................2 1.3.1国外研究现状...........................................2 1.3.2国内研究现状...........................................3 1.4课题的研究概况.............................................4
1.4.1课题的研究目的和意义...................................4 1.4.2 课题的研究内容........................................4 1.4.3 慢走丝线切割机床走丝系统的发展趋势....................5
2 线切割加工理论基础及张力执行元件.........................7
2.1 电火花线切割的加工原理...................................7 2.2 线切割加工工艺...........................................8 2.2.1 线切割加工的工指标 ..................................8 2.2.2 线切割加工的基本工艺规律.............................8 2.3磁粉制动器的介绍........................................10 2.4磁粉制动器的结构及其工作原理............................11 2.5 磁粉制动器的电气工作特性...............................13 2.5.1 激励电流和转矩的关系..............................13
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2.5.2 滑差工作特性......................................14 2.5.3 动作特性..........................................14 2.6 磁粉离合器和制动器的选用..............................15 2.7本章小结..............................................16
3 装置的方案设计..........................................17
3.1走丝系统总体结构.........................................17 3.2 低速走丝线切割机床张力装置及种类........................18 3.3 控制系统方案............................................20
3.3.1 控制系统主控单元的选择..............................20 3.3.2 运动控制卡..........................................21 3.3.3 步进电机及其驱动器..................................22
3.3.4 D/A模块............................................22 3.4 走丝系统的数学模型.....................................23 3.5 张力控制系统的传递函数.................................25 3.6 本章小结...............................................26
4 慢走丝线切割机床走丝机构的设计与计算....................27
4.1 储丝筒电机的选用.........................................27 4.2 储丝筒联轴器的选用.......................................27 4.3 储丝筒的材料选取.........................................28 4.4 齿轮副的设计与计算.......................................29 4.5 丝杠副的选用及计算.......................................30 4.6 线切割机床储丝筒导轨的选择...............................31
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