【摘要】：絕緣硬脆材料具有絕緣性好、耐腐蝕、耐高溫、硬度高等特點(diǎn),目前在航空航天、生物醫(yī)學(xué)、化工、冶金等領(lǐng)域受到廣泛應(yīng)用。由于其本身的高硬度和高脆性特點(diǎn),傳統(tǒng)的機(jī)械切削加工方法難以完成微細(xì)結(jié)構(gòu)的加工,電化學(xué)放電加工方法是目前較為合適的一種加工方法。本文針對絕緣硬脆材料微細(xì)結(jié)構(gòu)的加工技術(shù),開展了電化學(xué)放電加工方法的研究。本文首先分析了電化學(xué)放電加工機(jī)理,詳細(xì)闡述其加工過程和材料去除原理,總結(jié)了目前常規(guī)電化學(xué)放電加工方法存在的問題:隨著加工孔深度的增加,工具電極端部工作液更新困難,氣膜難以形成,放電集中在入口處,導(dǎo)致入口直徑過大,加工速度和加工質(zhì)量降低。針對這些問題,提出了倒置電化學(xué)放電加工方法,采用工件在上工具電極在下的布局形式,利于形成穩(wěn)定氣膜,維持該區(qū)域放電加工;工具電極的旋轉(zhuǎn)運(yùn)動利于工作液更新以及加工屑的排出。在此基礎(chǔ)上,搭建了倒置電化學(xué)放電加工平臺。利用搭建的倒置加工平臺,開展微小孔的加工工藝實(shí)驗(yàn),并與常規(guī)正置加工方法進(jìn)行了對比實(shí)驗(yàn)。通過采集加工中的電流信號,分析了倒置加工特性;分析了加工電壓、工作液濃度、進(jìn)給速度、旋轉(zhuǎn)運(yùn)動等參數(shù)對倒置加工的影響,對比了兩種加工方法加工的孔的入口直徑、加工深度、孔的錐度和加工重復(fù)性等指標(biāo)。實(shí)驗(yàn)結(jié)果表明,倒置旋轉(zhuǎn)加工方法能夠促進(jìn)工具電極端部工作液更新,形成穩(wěn)定氣膜,減少孔入口處的放電,從而提高加工速度和加工重復(fù)性,減小入口直徑和錐度。針對微晶云母陶瓷上的拉瓦爾噴管加工,設(shè)計了合理的工藝流程,應(yīng)用電化學(xué)放電加工方法,進(jìn)行微孔加工實(shí)驗(yàn)研究。實(shí)驗(yàn)中采用螺旋工具電極,進(jìn)一步提高孔內(nèi)工作液循環(huán),維持工具電極端部放電,減小了入口直徑,提高了加工速度,加工出符合要求的通孔。設(shè)計了超聲加工平臺,加工出拉瓦爾噴管。上述研究結(jié)果表明,本文提出的倒置電化學(xué)放電加工方法,在非導(dǎo)電材料的微細(xì)結(jié)構(gòu)加工中有很大的潛力,值得進(jìn)一步深入研究。
[Abstract]:Hard and brittle insulating materials are widely used in aerospace, biomedical, chemical, metallurgical and other fields because of their good insulation, corrosion resistance, high temperature resistance and high hardness. Because of its high hardness and high brittleness, the traditional machining method is difficult to finish the micro-structure machining. Electrochemical discharge machining is a more suitable machining method. In this paper, electrochemical discharge machining (EDM) has been carried out on the micro structure of hard and brittle insulating materials. In this paper, the mechanism of electrochemical discharge machining is analyzed, the machining process and material removal principle are described in detail, and the existing problems of conventional electrochemical discharge machining methods are summarized: with the increase of hole depth, The working fluid of the electric extreme part of the tool is difficult to renew, the gas film is difficult to form, and the discharge is concentrated at the entrance, which leads to the excessive diameter of the inlet and the decrease of the machining speed and quality. Aiming at these problems, an inverted electrochemical discharge machining method is put forward, which adopts the layout of the top tool electrode in the workpiece, which is conducive to the formation of stable gas film and the maintenance of the discharge machining in this area. The rotating movement of the tool electrode is beneficial to the renewal of working fluid and the discharge of machining chips. On this basis, an inverted electrochemical discharge machining platform was built. Using the inverted machining platform, the machining process experiment of micro hole is carried out, and the contrast experiment is carried out with the conventional positive machining method. The characteristics of inverted machining are analyzed by collecting the current signal in machining. The effects of the parameters such as voltage, working fluid concentration, feed speed and rotation motion on the inverted machining are analyzed. The inlet diameter, machining depth, hole taper and processing repeatability of the two machining methods are compared. The experimental results show that the inverted rotating machining method can promote the working fluid renewal of the electric extreme part of the tool, form a stable gas film, reduce the discharge at the entrance of the hole, improve the machining speed and repeatability, and reduce the inlet diameter and taper. Aiming at the processing of Laval nozzle on microcrystalline mica ceramics, a reasonable technological process was designed, and the experimental study of micropore machining was carried out by using electrochemical discharge machining method. The spiral tool electrode is used in the experiment to further improve the working liquid circulation in the hole, to maintain the electric extreme discharge of the tool, to reduce the inlet diameter, to increase the machining speed and to produce the through hole that meets the requirements. The ultrasonic machining platform is designed and the Laval nozzle is machined. The results show that the inverted electrochemical discharge machining method proposed in this paper has great potential in the fabrication of non-conductive materials, and it is worthy of further study.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG662

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本文編號：2348707