【作者】 袁立新；

【导师】 徐家文；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 喷射液束电解—激光复合加工是将电解加工与激光加工进行复合的新型加工方法，其加工原理是在激光加工快速去除材料的同时，利用喷射电解液束的电解作用在线去除再铸层，提高加工小孔的表面质量。为了将该技术使用于工程应用，研究和掌握激光束在动态喷射液束中的衰减特性，研制喷射液束电解—激光复合加工系统，深入研究该技术的加工工艺，具有重要的现实意义。为此，本文以喷射液束电解—激光复合加工技术应用于工程实际为目的，进行了以下研究工作：本文首先研究了动态喷射液束中激光的衰减特性。根据溶液对激光吸收、散射的理论分析，结合喷射液束电解—激光复合加工原理，分析了喷射液束中氢气微气泡对激光的散射特性，基于自制的专用试验装置，研究了激光在喷射液束中的衰减特性，为设计喷射液束电解—激光复合加工系统提供重要的依据。其次研制了喷射液束电解—激光复合加工系统。1)根据复合加工对喷射液束的要求，通过合理设计装置结构和选择喷嘴材料，设计了喷射耦合装置，该装置实现了激光束与喷射液束的精确耦合，使得喷射液束的破碎长度大于10mm，满足了复合加工对喷射液束的的要求；2)根据喷射液束电解加工的需要，研制了高压脉冲电源，该电源以555振荡电路为核心，以MOSFET为功率开关管，用脉宽调节和脉间调节相结合的方法，使输出电压和电源频率连续可调；3)基于激光在动态喷射液束中的衰减特性和提高激光在喷射液束中的加工效率，设计了喷射液束电解—激光复合加工分时控制系统，实现了喷射液束电解—激光分时控制的多种加工方式，解决了激光在喷射液束中严重衰减问题。最后利用喷射液束电解—激光复合加工系统，进行了复合加工工艺试验研究。1)基于扫描电镜和金相显微技术，研究了喷射液束电解—激光复合加工的再铸层。研究结果表明：喷射液束电解—激光复合加工能够将电解加工与激光加工进行复合，并能100％地去除孔壁的再铸层，提高激光加工表面质量；2)使用单因素分析法，对某新型镍基高温合金片进行喷射液束电解—激光复合打孔，研究工艺参数对表面粗糙度和晶间腐蚀的影响规律。研究结果表明：采用复合电解液加工小孔的表面质量好于单一成份的电解液，当复合电解液的配比浓度为6％NaNO3＋3％～4％NaCl、电解液的温度为30℃～40℃、电源电压为200VDC～300VDC时，能得到粗糙度小和晶间腐蚀少的加工效果；3)应用响应曲面法设计了二次回归正交试验，通过加工不锈钢材料小孔试验建立了材料去除率和再铸层残留率的二次回归方程，总结了喷射液束电解—激光复合加工的工艺规律，利用优化的工艺参数进行了系列加工实例。通过本文的理论分析和工艺试验研究，进一步验证了喷射液束电解—激光复合加工能够有效去除再铸层，表明了喷射液束电解—激光复合加工技术具有诱人的工程应用前景，同时本文新研制的复合加工系统和工艺试验研究结果为该技术的工程应用提供了重要依据。更多还原

【Abstract】 The hybrid processing of jet electrochemical machining and laser beam machining(JECM-LBM) is a new processing method which is combined with laser processing andelectrochemical machining. The processing principle is that the material is removed mainly bylaser processing and the recast is removed by the electrochemical reaction with the surfacematerials, as well as improve the overall quality of laser-drilled holes. It will be great significanceto thoroughly grasp JECM-LBM core techniques and JECM-LBM processing technology tofabricate hole and groove structures with the size (from0.1mm to1.0mm) which exists widely inaerospace industry.In order to apply the new technology to the engineering, the main research contents wereincluded:1) The properties of laser attenuation were researched in dynamic jet electrolyte. According tothe theoretical analyses of laser absorption and scattering of solution and the principle ofJECM-LBM, the properties that laser is scattered by bubble in jet electrolyte were analyzed. Theproperties of laser attenuation in the jet electrolyte were researched with self-designed andmanufactured set up. The results of the laser attenuation in the jet electrolyte provided theimportant basis for the design of the JECM-LBM experimental system.2) The experimental system of JECM-LBM was developed. Firstly, based on the requirementsof jet electrolyte, the injection coupling device was developed by optimizing the device structureand selecting reasonably the nozzle materials. The device can implement the precise coupling laserwith the jet electrolyte. The breaking length of the jet is more than10mm which meet therequirements of JECM-LBM processing. Secondly, the high voltage pulse power supply wasdeveloped according to the need of jet electrochemical machining. It used555oscillation circuitand MOSFET mainly, and combined the PFM and PWM, and then the output voltage, current, andthe frequency of power supply could be adjusted continuously. At last, the time shared controlsystem was developed, which meet the variety of processing methods of jet electrochemicalmachining and laser machining. The severe laser attenuation was overcome in the jet electrolyte.3) The processing rules have been thoroughly researched by using the experimental system.Firstly, based on the scanning electron microscope and metallographic techniques, the recast layerin JECM-LBM was studied. The results shows that the JECM-LBM is combined with laserprocessing and electrochemical machining, and the recast layer can been completely removed byelectrolysis to improve the hole quality. Secondly, in order to study the rules of process parameterson surface roughness and inter granular corrosion, the JECM-LBM drilled on the new type nickel based super alloy. The results show that the hole quality drilled by JECM-LBM using compositeelectrolyte is better than using the single electrolyte. For achieving the small roughness and lessinter granular corrosion, the process parameters are6％NaNO3＋3％～4％NaCl compositeelectrolyte,30℃～40℃electrolyte and200VDC～300VDC supply power. At last, theorthogonal experiments were designed by the response surface methodology(RSM), and the twoquadratic regression equations were achieved with drilling on stainless steel shell. Theprocessing rules of JECM-LBM have been summarized by the experimental results. Usingoptimum processing parameters, a series of samples were machining with JECM-LBM.The above theoretical analysis and experimental investigation were shown that the hybridprocess has great potential as a new technical approach in engineering for removing the recastlayer to obtain the high machining quality. The new system of JECM-LBM and the experimentalresults in the paper can provide important reference for the application of the new process inaeronautical engineering.更多还原