Development of a New Internal Finishing of Tube by Magnetic Abrasive Finishing Process Combined with Electrochemical Machining

Abstract

The research proposes a new internal surface magnetic abrasive finishing (MAF) process, which compounded with electrochemical machining (ECM) to decrease machining time. The electrochemical process changes the morphology of the aluminum tube internal surface, producing an oxidation film. Then, we removed the film by magnetic abrasive finishing, results in minimized surface roughness in a significantly reduced processing time when compared to the conventional MAF. In this research, a new experimental set up with a tool that capable of magnetic abrasive finishing and electrochemical finishing was designed and developed to study the machining feasibility. The newly developed finishing method demonstrated simultaneous process of aluminum oxide film formation by ECM and its removal by MAF. This process plays a significant role in preventing the deepening of the pit during ECM and speed up the planarization. The method was developed step by step; firstly, ECM and MAF were conducted in two separate processes. In the second experiment, we modified the finishing conditions to facilitate one-stage finishing method. An investigation of the finishing surface is focusing on the pit size that formed by ECM. The pit size indicated the residue of oxide film because it is a part of the oxidation film construction. Pits morphology changes were observed for certain finishing time to determine the minimum finishing time for its removal. Surface roughness and SEM photograph of the finishing surface were recorded and studied.