Feasibility study of laser and in-situ ECM of array holes

Abstract

Aiming at the issues of low machining efficiency and difficulty in keeping consistency of machining accuracy of micro array holes with high surface quality. This paper proposed a laser and in-situ electrolytic machining technology for processing array holes, which utilized the advantages of high laser machining efficiency and good surface quality electrochemical machining (ECM). Firstly, laser was used to perform high-efficiency drilling of prefabricated micro array holes on workpieces that was covered with insulating layer, and then the recast layer and taper of prefabricated holes were removed by ECM. To verify the feasibility of the proposed method, laser prefabricated of the array holes with the diameter of 0.8 mm and the in-situ electrolytic recast layer removal were carried out on the Inconel 718 workpiece. Influences of laser scanning speed, defocusing distance, scanning times and insulating plate thickness on the taper of prefabricated hole were investigated experimentally. The optimized laser processing parameters were as follows: scanning speed 60 mm/s, defocusing distance 1.5 mm, scanning times 50, and insulating plate thickness 0.4mm. Results of in-situ ECM showed that the recast layer on the surface of the laser processed holes could be removed, indicating that the laser and in-situ ECM could achieve high efficiency and high precision machining of micro array holes without recast layer.