UV laser machining of biomaterial composite

There is little study on the wavelength-dependent cutting process of biomaterial composites, such as cheese. In addition to scientific curiosity, there is also a need from the dairy industry to investigate the feasibility of laser machining/marking of cheese. This paper studies the wavelength and energy fluence dependence of laser drilling and cutting of cheese with a Q-switched pulse Nd:YAG laser at 3rd and 4th harmonic wavelengths of 355 and 266 nm. Cutting depth with a laser beam at 355 nm is significantly smaller than that with a laser beam of 266 nm. While damages and burns occurred around and inside the cutting cross-section with the laser beam of 355 nm, the laser beam of 266nm produced high quality cutting and drilling. Patterns on cheese were machined with the laser beam of 266 nm after a design pattern was transported from CAD software into laser control system. The cutting speed was low since the repetition rate of the laser used is 20Hz. With UV laser sources of higher repetition rate and higher power, the cutting speed and depth can be improved significantly.