STUDIES ON THE EFFECT OF TOOL ROTATION IN MICRO-ULTRASONIC DRILLING OF HIGH ASPECT RATIO HOLES

Abstract

Miniaturization is the need of hour as it saves the space, time, material, and energy as well. Therefore the demand of miniaturized features, components and products is rapidly increasing in industries. These micro-products includes the features such as microholes, and microchannels which are extensively used in microfluidics, Bio-MEMS, microelectronic chip (heat transfer) applications and Lab-on-a-chip. These micro-features are fabricated by conventional as well as non-conventional methods. Conventional methods include micro drilling whereas non-conventional techniques are Lithography, Chemical etching, Embossing, LIGA and Laser fabrication etc. Glass is commonly used material in these kind of application because it is chemically inert to most of the materials, have good optical properties, hydrophilic, non-porous suitable for prototyping and inexpensive as well. However being a fragile material, it is very difficult to machine by conventional method. Whereas LIGA, lithography and chemical etching are unable to generate high aspect ratio micro-features with good dimensional accuracy. Moreover these methods are time consuming and costly as well. Laser fabrication have the limitation to produce heat affected zone due to which workpiece properties change which further affect the useful life of product. Therefore there is a need to develop such process which can develop 3D complex micro-features at faster rate without altering the properties of workpiece.