DEVELOPMENT OF MICRO CHANNELS USING ULTRASONIC MICROMACHINING

Abstract

Fabrication of microchannels is evolving by the day with newer, cheaper, faster and more effective methods being explored on a continuous basis. Use of micro ultrasonic machining as a cost effective method for fabrication of 3D microchannels had not been investigated till recently. Insufficient research in application of micro-USM towards machining complex micro channels gives new opportunities for research. Titanium with its excellent biocompatibility and superior properties such as chemical inertness, corrosion resistance, oxidation resistance, high fracture toughness, high strength at elevated temperature and relatively high heat transfer rate as compared to the hard and brittle materials being used currently is of high interest in micro electromechanical systems (MEMS) for the fabrication of micro-channels and micro-fluidics networks like micro heat exchangers. Hence, an investigation has been carried out to develop microchannels on titanium using ultrasonic micromachining. Boron carbide abrasive slurry was used for the experimentats. The effects of various input process parameters like slurry concentration, abrasive size, power rating and static load were investigated on the machining outputs- material removal rate and tool wear rate using Taguchi's design of experiment approach. Microchannels with minimum width of 120 pm and maximum depth of 630 p.m were fabricated with reasonable accuracy. The analysis of the successfully developed microchannels showed that the response variables were strongly influenced by input parameters, with abrasive size having the maximum effect, followed by the ultrasonic power rating. iii