Tool-based compound micro/nano-machining

In recent years, there has been marked increase in demand for product miniaturization in industry segments ranging from aerospace, automotive, medical devices and information technology. Furthermore, recent fervour in nanotechnology has also created urgent need to developed interfacing devices from the nano world to these miniaturized products. Compound micro-machining is the most promising technology for the production of miniaturized parts and this technology is becoming more and more important and popular because of growing demand for industrial products with not only increased number of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. In this paper, the development efforts in micro/nano-machining based on solid tools (tool-based micro/nano-machining) in NUS are introduced. Tool-based micro/nano machining is based on development of conventional precision engineering technology to achieve micron level features, sub-micron accuracy and nanometer level surface finish. In order to achieve meaningful implementation of micro-machining techniques, this research seeks to address four important areas; namely (a) development of machine tool capable to do both conventional micro-machining including micro-turning, micro-milling, etc. and non-conventional micro-machining including electrical discharge machining (EDM), wire-cut EDM (WEDM), wire-electrical discharge grinding (WEDG) of hybrid micro-machining, (b) process control, (c) process development to achieve necessary accuracy and quality, and (d) on-machine measurement and inspection. An integrated effort in these areas has resulted in successful fabrication of micro-structures that is able to meet the miniaturization demands of the industry. This paper presents few tool-based approaches integrating micro-EDM, micro-EDG, micro-turning and micro-grinding to produce miniature components. In the area of nano-machining machine tool and process developments have also been carried out for electrolytic in-process dressing (ELID) grinding and ultra precision machining using single point and poly crystalline diamond tools to produce nano surface finish on hard and brittle materials. An ultra-precision diamond turning machine has been developed which incorporates a fast and fine tool servo system to produce nano-precision surfaces and features.