Complex shaped micro-channels generation using tools fabricated by AWJ milling process

Abstract

Fabrication of complex shape micro-channels is a major challenge for manufacturing industries. Currently in commercial applications, lithography and non-conventional machining processes like lasers, electro-discharge machining (EDM) and chemical etching are commonly used for fabrication of these channels. In the present work, a novel Abrasive water jet (AWJ) milling based tool fabrication strategy has been proposed and implemented to make micro-tools (die/ electrode). The path strategy for jet movement is considered in a manner to selectively remove metal from a piece of material such that the resulting three-dimensional features become the required die shape that can be used as tool for the texturing process. Micro-tool of complex shape as fabricated on hard material (EN 31) sheet of 12 mm thickness and its geometry were analysed by controlling the step over (SO) distance. Hydraulic control based hard press contact texturing setup was developed to analyse the performance of such fabricated tools. Experiments were conducted on soft materials like, PMMA, Copper, Brass, aluminium and Nylon. Taper along the depth of the channels was observed because of the taper of the tool during fabrication. During fabrication, width of the tool less than 200 μ m was found wavi in nature as there was not enough backing material present to bear the side wise jet pressure of impinging jet. Buckling on the tools was observed with tool height greater than 1 mm.