Laser micro-milling of bio-lox forte ceramic: An experimental analysis

Laser micro-milling process (LMMP) is one of the competent machining processes to fabricate micro-features in a wide range of materials. This paper presents the results of an investigation on the process capability of Nd:YAG laser to produce micro-channels on bio-lox forte material that has numerous applications in the medical field. The main objective of the current study is to produce the micro-channels in the bio-lox forte material with the desired/target geometry and acceptable surface quality. Preliminary experiments were conducted to select the appropriate ranges of the key input laser process parameters including laser scanning speed (100-500 mm/s), pulse frequency (5-25 kHz), laser intensity (86-96%), scanning strategies (line, net and cross) and track displacement (5-20 mu m). The effects of the selected process parameters on the quality of the micro-channel' were evaluated by analyzing the dimensional accuracy, material removal rate, surface roughness and surface morphology. The experimental results reveal that the often neglected parameters of track displacement and scanning strategy have a profound influence on the surface morphology, roughness and dimensional accuracy of the fabricated micro-channels. The micro-channels with a minimum surface roughness of 1.81 mu m and a averge dimensional error of < 10% were fabricated on the bio-lox forte material. Furthermore, smoothed surface morphology with no elemental/phase changes could be achieved while employing cross scanning strategy at a combination of scanning speed of 200-250 mm/s, pulse frequency of 5-7 kHz, 90-92% and track displacement of 10 mu m.