The application of a turning tool as the electrode in electropolishing

摘要

In the current study, electropolishing using a turning tool as the electrode for several die materials following turning is investigated. The proposed method uses a traveling electrode instead of the mating electrode as in conventional ECM, hence the dimensional error can be controlled more effectively. Further, the method removes a certain limited amount of material, therefore the complex pre-polishing as required in the soakage electropolishing method is eliminated. This process can he used for various turning operations including end turning, form turning, and flute and thread cutting. Through the attachment of simple equipment, electropolishing can follow the cutting on the same machine and chuck. The electrode of the turning tool travels and polishes the machined surface of workpiece with electrical current. Among the factors affecting the electropolishing, the design of tool electrode is discussed primarily. A common turning tool can be used in electropolishing, while a slight modification of tool geometry achieves optimal polishing at low cost. The controlling factors include the chemical composition and concentration of the electrolyte, the initial gap width, and the flow rate of the electrolyte. The experimental parameters are the current rating, the electrode geometry, the die material, the workpiece rotational speed, and the electrode feed rate. Turning tools with larger angles and smaller cross-section are associated with larger discharge space and thus polish better. The most significant factors in tool design for improving the surface roughness include the end clearance angle and the end cutting edge angle. A smaller nose radius is associated with higher current density and provides a faster feed rate and a better polishing effect.