Abstract
The current study discusses the surface finish of several common die materials, of which the inner holes are electropolished and electrobrightened by different types of feeding electrodes. In the experiment, two types of electrode are used with the application of continuous direct current and axial electrode feed. The controlled factors include the dimension of the electrode as well as the chemical composition and the concentration of the electrolyte. The parameters are current rating, electrode geometry, die material, electrode rotational speed and feed rate. It was found that electrobrightening after reaming requires quite a short working time, whilst the electropolishing avoids the need for reaming, thus makes the total cycle time less than electrobrightening. The electrode of boring cutter type performs better in the current investigation.