JK Lasers has developed a method of processing Alumina ceramic (Al2O3), a material that is used for medical prostheses, ballistic armour and laser tubes but is prone to cracking from thermal stress.
Using JK Lasers’ single mode 200W fibre laser (JK200FL) with built-in modulation and a lamp-pumped pulsed Nd:YAG laser (JK100P), a high standard of finish could be achieved with Al203. Using the JK200FL, good quality cuts in Al2O3 up to 1mm deep are possible, using pulse widths as short as 5µs. The finish quality is achieved by precisely controlling spot size, peak power, pulse duration and frequency. With the JK100P, a combination of high peak power (10kW), short pulses (15-200µs) and high repetition rate (2,000Hz) also make this laser well suited to cutting Al2O3, up to 2mm thick. It is possible to cut up to 3mm with multi-passing.
The results of the development show that these two JK lasers can machine Al2O3 between 96 and 99.7 per cent purity. Optimised laser and processing parameters help minimise heat input, significantly reducing the risk of thermal stress which can lead to cracking. The work also found that large scattering of the laser beam, which can be seen at some common wavelengths, can be overcome through a combination of high peak power, short pulses and short wavelengths (1µm).