Q: What is ECM processing of bearing ring raceway?

A: ECM processing is to use electrochemical mechanical processing to improve the productivity and roughness of ultra-finished products. The mechanism of ECM processing is: first, a thin oxide film (passivation film) is formed on the surface of the part by electrochemical anode dissolution, and then the workpiece is mechanically scraped and activated by a suitable abrasive tool. During the scraping process, the pressure of the abrasive tool is small and insufficient to cut the metal. Therefore, only the passivation film at the microscopic convex points on the surface can be scraped off to activate the area. The microscopic concave points cannot be touched by the scraping action of the abrasive tool and are not activated by the scraping film. When the activated surface faces the anode again, a new round of electrochemical removal begins. At this time, the microscopic concave points will hinder further electrochemical film removal due to the protection of the passivation film. The reciprocating cycle allows the microscopic convex points on the machined surface to be quickly removed and the surface to be quickly leveled. Generally, the surface roughness Ra can be reduced to below 0.025 μm after ECM processing.

ECM processing, with its characteristics of self-feedback, controllable additional feedback, can simply and effectively improve the surface quality and precision of parts processing. It is an innovative process method that has been tested in practice. ECM processing of the inner and outer ring raceways of rolling bearings can greatly reduce the surface roughness of the raceways, reduce the waviness, obtain a more ideal surface micro-geometry, improve the mechanical and physical properties of the bearing raceway surface layer, thereby greatly reducing noise and improving the performance and life of the bearing. The use of ECM processing technology to replace the current bearing industry raceway oilstone superfinishing or raceway mechanical polishing process can greatly reduce the raceway surface roughness, further improve the roundness and waviness of the raceway, and the vibration value of the finished deep groove ball bearing Z2 group can reach more than 95%, and has 80% of the Z3 group reserve. The bearing life will be greatly improved compared to the life after general superfinishing.