Electrochemical machining for micro holes with high aspect ratio on metal alloys using three-electrode PPS in neutral salt solution

• Published in: International journal of advanced manufacturing technology Vol. 93; no. 5-8; pp. 1903 - 1913
• Main Authors: Kong, Quan Cun, Li, Yong, Liu, Guo Dong, Li, Chao Jiang, Tong, Hao, Gan, Wei Min
• Format: Journal Article
• Language: English
• Published: London Springer London 01.11.2017; Springer Nature B.V
• Subjects: Arrays; Austenitic stainless steels; CAE) and Design; Computer-Aided Engineering (CAD; Diameters; Electrochemical machining; Electrodes; Electrolytes; Engineering; High aspect ratio; Industrial and Production Engineering; Localization; Machining; Material removal rate (machining); Mechanical Engineering; Media Management; Metal plates; Microholes; Original Article; Power supplies; Saline solutions; Surface properties; Surface roughness; Thickening; Workpieces; Electrochemical machining (ECM); High aspect ratio; Electrolyte; Micro holes; Gas inhibition and dissolution promotion (GIDP); Three-electrode pulse power supply (PPS); Metal alloys
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-017-0645-y

To get micro holes with high aspect ratio on metal alloys by electrochemical machining (ECM) process, the mutual restricted problems between machining localization and efficiency are researched. By analyzing the thickening process of passive film, the mechanism of gas inhibition and dissolution promotion (GIDP) is explored. Thereby, a three-electrode pulse power supply (PPS) is designed to acidize on the workpiece/solution interface, for both better machining localization and efficiency. Micro ECM experiments, using the three-electrode PPS in neutral salt solution as electrolyte, are carried out on 304 stainless steel and 18CrNi8 alloy, in which a micro hollow electrode is used to flush electrolyte under high-pressure supply. It is found that the material removal rate (MRR) is increased by at least 80% and surface roughness R a is dropped by 40%, compared to those of two-electrode PPS. Micro array holes with diameter of about 175 μm are machined through metallic plates with thickness of 0.5 and 1.1 mm respectively. The micro array holes obtained have high consistent precision, good surface quality, and aspect ratio up to 6.5. Experimental results show the feasibility of micro ECM techniques proposed for micro hole with high aspect ratio.