Design and performance assessment for use in ultrasonic-aided cylindrical surface polishing

Abstract

This paper studies the performance assessment of ultrasonic-aided electropolishing and ultrasonic-aided pulse-electropolishing of external cylindrical surfaces by three groups of design electrode recommended in a previous publication by the author. Six types of feeding electrode are connected with continuous direct current in an electropolishing experiment. It requires no expensive special-purpose equipment nor high material removal as does conventional electrochemical machining, it offers fast improvement of the surface roughness and reduces the residual stress on the workpiece in a new area in electropolishing. The control factors include die material, chemical composition and concentration of the electrolyte, electrolyte temperature, flowrate of the electrolyte, initial gap width, electrical current rating, workpiece and electrode rotational speed, and electrode feed rate. The experimental parameters are the frequency and power level of ultrasonics, the pulse period, and the electrode design. The design change from inner taper to inside pins for full-ring electrodes performs well. The designed flat arrowhead electrode with flute back rake angle and side rake angle comes out better than that of the double-flute arrowhead electrode. The disc electrode with pins attached on edge performs better than the disc with a discharge flute; and the polishing effect of disc-form electrodes is the best, followed by arrowhead electrodes, and ring-form electrodes. Using adequate electrode geometry as well as the ultrasonic aid, an effective and low-cost electropolishing of external cylindrical surface is presented.