Intelligent laser machining system for multi-function processing of superhard materials

Abstract

An intelligent laser machining system is developed for precision processing of superhard materials, such as diamond, silicon carbide, silicon nitride, cubic boron nitride, etc. Multiple processing functions, such as laser cutting, laser engraving, laser cleaning and polishing, can be realized by automatically adjusting laser beam parameters. The laser wavelength is 532 nm that is obtained by the second-harmonic generation of a diode-pumped solid-state laser at 1064 nm. The processing system is highly intelligent and automated, from surface scanning and measurement to self-adjustment of laser beam parameters and motion control variables during processing. In our processing, the workpiece is first scanned using a laser sensor and a 3-D profile of the workpiece is created for customer evaluation. Then, with operator’s input of processing requirements, an optimal processing procedure is designed in terms of comprehensive consideration of machining efficiency, processing duration, machine cost, surface quality, material loss, etc. Next, the material is flatten to a certain flatness by using a suitable engraving process, followed by polishing to a certain roughness, and finally cut to shaped pieces. In both the procedure design and material processing, an artificial neural network method is used in the optimization and adjustment of laser beam and motion control parameters. In the experiment of silicon carbide processing, >10-mm thick bulk materials can be cut with nearly vertical edges and polished with ~0.1 um roughness of surface. The system exhibits broad prospects in the processing applications of superhard materials.