Fine-finishing of stepped cylindrical workpiece using magnetorheological finishing process

Abstract

A various stepped cylindrical workpieces are commonly known for their functionality in different industrial components such as hydraulic or pneumatic actuators, plungers, etc. However, fine-finishing of stepped cylindrical workpiece (made of softer materials) is difficult by grinding operation because of its rigid tool structure. This tool structure is made by the rigid bonding of abrasive particles to a comman wheel. When this rigid tool approaches the workpiece surface, it results with different surface defects such as pits, scratches, grooves, cavity, etc. To overcome such circumstances, magnetorheological (MR) processes can be used. These processes use MR polishing fluid for fine-finishing of different materials ranging from soft to the harder type. In the present work, the MR finishing process is used for finishing of the external surfaces of stepped cylindrical workpiece. The MR finishing tool is developed in such a way that it is flexible in accordance with the diameter of cylindrical workpiece. In this tool structure, the permanent magnets (made up of neodymium NdFe35) have been used for retaining the MR polishing fluid on its surface. Experiments have been conducted on the aluminium stepped workpiece in order to check the practicability of the present developed tool. The results revealed that a fine-finishing of stepped cylindrical workpiece with a surface roughness Ra value as 62 nm is achieved on aluminium workpiece. Also, the mechanism of material removal involved during the finishing process has been analyzed mathematically. Removal of material from the external surface of single step of aluminium workpiece has been confirmed mathematically with the help of the present developed MR finishing tool.