MICROFABRICATION BY MICRO-MACHINING AND MICRO-JETTING

MICROFABRICATION BY MICRO-MACHINING AND MICRO-JETTING

Abstract:

With the continuing trends towards product miniaturization, there is corresponding demand for microfabrication processes to produce micro-components. Fabrication processes, such as micromachining and layer manufacturing, have potential for appropriate downscaling as alternative microfabrication processes to those commonly used in the fabrication of semiconductor devices. Micromachining is a material removal process while layer manufacturing is a material additive process. Some of the challenges and achievements in the development of the control system and processes for microfabrication by micromachining based on EDM, and layer manufacturing based on micro-jetting will be presented. A multi-process micromachining system has been developed to primarily employ µ-EDM, but in combination with other ‘tool-based processes’ such as µ-turning and µ-milling, including wire-EDM. On-machine measuring and verification devices are incorporated to achieve high dimensional accuracy of the fabricated micro-structures. With computer numerical control, complex micro-structures can be produced. Components with high aspect ratio, such as micro-cylindrical features of shafts and holes (e.g. less than 6µm diameter and 1500 µm length) through non-metallic and metallic components, micro-grooves and lenses at nano-finish on glass, and other complex micro components have been successfully manufactured by the micro-process microfabrication. Another development involves layer-by-layer 3D microfabrication. It is centered on multi-material micro-jetting, using multi-nozzle drop-on-demand approach. Different types of actuators are employed to impart the micro-jetting to suit the microfabrication requirements. A computer-controlled system with modular multi-nozzle units for dispensing different types of materials and on-machine vision-based system has been developed. Studies have been conducted on developing and understanding different types of micro-jetting nozzles through simulation and experimental studies, particularly on the behaviors of micro-droplets produced. Application developments include microfabrication of micro-devices, scaffold and cell printing, and drug patch.