Synchronous finishing processes using a combination of grinding and electrochemical smoothing on end-turning surfaces

Abstract

A new finishing mode has been utilized as an effective finishing tool design with an electrode and a nonconductive grindstone to execute grinding and electrochemical smoothing synchronously. This mode can be used for various end-turning operations. Through simple equipment attachment, grinding and electrochemical smoothing can follow the cutting process on the same machine. Among the factors affecting electrochemical smoothing, grinding performance combined with electrochemical smoothing, is primarily discussed. In the experiment, different types of electrodes are used with continuous and pulsed direct current. The control factors include die material, chemical composition, and concentration of the electrolyte. The experimental parameters are finish tool and workpiece rotational speed, flow rate of electrolytes, gap width between electrode and workpiece, electrical current density and pulsed period, and finishing tool geometry. High workpiece and electrode rotational speed produces a better finish. A thin electrode is associated with higher current density and provides larger discharge space for a better finish. Pulsed direct current can promote the effect of electrochemical finishing. Decreasing the height of the finish tool to a partial-form tool is associated with less restricted electrolyte flow and more discharge space, which creates better finishes than the full-form tools. The grindstone, with an adequately convex shape, also appeared to have an adequate initial gap width between the electrode and workpiece, which matches enough current density and obtains a better finish. The most effective geometric design for the finishing tool and the advantage of the low-cost equipment in electrochemical smoothing, following end-turning, is investigated in this study.