A novel CAD/CAM tool for excimer laser ablation-machining process

This paper reports on the development of a novel software system for excimer laser ablation machining processes. The system’s algorithms use the 3D geometry of a microstructure, defined in a CAD model, and parameters that influence the process (etch rate, wall angle, stitching errors, etc) to automatically generate a precise NC part program for the excimer laser machine. The algorithms and a prototype software system have been developed for the step-and-repeat laser ablation technique and extended to include the workpiece-dragging technique. The latter, achieves both higher surface accuracy and smoothness within the sub-micron range. The algorithm enables various mask sizes to be used to control accuracy of the machined part and development includes tool path optimisation and processing time reduction. The software simplifies part program creation and is useful for excimer laser operators who currently use a tedious trial and error process to generate microstructure parts. The benefits of the software include more accurate microstructures and reduced overall costs of the process itself. The performance of the system has been verified by NC part program generation for several 3D microstructures and subsequent machining trials. The analysis of stitching and edge errors is reported, and comparisons of 3D models with the machined surfaces are given. Microstructures were analysed using Scanning Electron Microscopy (SEM), Laser Scanning Confocal Microscopy (LSCM) and optical microscopy.