在激光电化学复合微细加工系统中,利用透光导电的氧化铟锡(Indium tin oxide,ITO)导电玻璃作为工具阴极,引入激光辐照能量,保证了激光电化学体系的高效复合。采用脉冲激光辐照和电化学溶解蚀除的方法对铝合金进行了加工试验,工件表面在均匀电场作用下所形成的钝化膜,在激光定域辐照的热力冲击作用下被破坏,使基体材料发生电化学反应,而非辐照区域则不发生反应,从而提高了电化学反应的定域性。研究了复合加工定域性受激光热力冲击和气泡折射影响的机理,根据试验结果分析了激光能量,加工电流以及不同加工方式对复合加工定域性的影响,采用优化的工艺参数,有效抑制了激光热影响区和电化学杂散腐蚀,实现了成形精度和表面质量均较好的三维槽腔加工。
By integrating indium tin oxide (ITO) conductive glass into the laser electrochemical micro machining system as tool cathode, the efficient combination of laser electrochemical machining is achieved with laser irradiation. In the established experimental system, the aluminum alloy is etched by the compound processing of laser and electrochemistry. The thermal-mechanical shock effect of laser local irradiation could remove the passivation layer in a uniform electric field, and the material at this zone is etched. However, the other regional material could not be removed because of the protection of the passivation layer, which enhances the localisation of electrochemical machining significantly. The influence mechanism of the thermal-mechanical shock of laser and the refraction characteristic of bubbles on the localization of combined machining is investigated theoretically. Based on the experiment result, the influence of the laser power, machining current and different processing methods on the localization of combined machining is also analyzed. The stray-current corrosion is restrained effectively and a three dimensional cavity with good shape precision and surface quality is acquired successfully with reasonable processing parameters.