| 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. |
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