Development of Barrel Finishing Machine to Improve Surface Finish of the Wire Arc Additive Manufactured Parts

Abstract

The wire + arc additive manufactured (WAAM) parts form wavy surfaces due to layer over layer deposition of the metal wire. These parts are often difficult to finish/clean for the intricate shapes and complex geometries. The barrel finishing technique which utilises abrasive media has been widely recognised as a mass finishing process. The commonly used designs for the barrel finishing process keeps the barrel either in the horizontal or vertical position. The proposed design has inclined barrel, taking advantage of both centrifugal and avalanche actions of forces produced by the vertical and horizontal barrel, respectively. The system utilises a barrel of diameter 400 mm and height 500 mm, supported by the two wheels on the periphery. A universal joint was used to transmit the motion from the power shaft to the barrel, which was also taking care of misalignment generated due to the eccentric loading. The effect of abrasive size and rotational speed was studied to determine the optimum finishing time for minimum surface roughness. The surface roughness (Ra) for representative corroded samples of various geometries was found to be decreasing and further increasing with processing time. The optimised finishing time was found to be in the range of 4-6 hours. The process was successfully implemented to finish WAAM parts having different geometries. © 2017 The Authors. Published by Elsevier B.V.