Fabrication and analysis of complex-shape tool for EDM by AWJM process

Abstract

In the present work, a novel AWJM-based tool fabrication strategy has been proposed and implemented to make EDM tools. The novelty of the work relies on the proposal of path strategy for jet movement that moves along two parallel paths while keeping the step over (SO) more than the diameter of nozzle (1.25d). The remaining protruded material in between two parallel passes can be utilised as an EDM tool. Following this procedure, micro-tools were fabricated and their geometry was analysed by varying the process parameters: SO, pressure and traverse speed, respectively, on a copper sheet of 6-mm thickness. All the parameters were kept constant in two passes to maintain tool accuracy on all sides. Micro-tools of different shapes (straight, curve) were fabricated. Geometry of micro-tools was measured by 3-D optical profilometer and processed using Vision 64 software. Digital and scanning electron microscopes were used to observe and analyse the microscopic behaviour of the machined surfaces (tool) namely, bottom surface, side wall and top surface. Tools thus fabricated were found to be of good quality except that some abrasive particles were found embedded into bottom surface. The response of the tools was analysed by performing the experiments on an EDM set-up, where the width of the channels was found to be uniform throughout.