Product Code: ICAL08_M1202

Nano-, Pico- and Femtosecond Laser Machining of Bioabsorbable Polymers and Biomedical Composites
Authors:
Assi Huttunen, Tampere University of Technology; Tampere Finland
Claire O'Connell, National University of Ireland; Galway Ireland
Gareth Williams, National University of Ireland; Galway Ireland
Petri Laakso, VTT Technical Research Centre of Finland; Lappeenranta Finland
Henna Niiranen, Tampere University of Technology; Tampere Finland
Mikko Huttunen, Tampere University of Technology; Tampere Finland
Richard Sherlock, National University of Ireland; Galway Ireland
Ville Ellä, Tampere University of Technology; Tampere Finland
Minna Kellomäki, Tampere University of Technology; Tampere Finland
Presented at ICALEO 2008

In this work, bioabsorbable polymers and biomedical composites were machined with three different lasers. Laser micromachining of grooves were studied using nanosecond ArF-excimer laser, diode pumped Nd:YVO4 picosecond laser, and femtosecond Ti:sapphire-laser. Profile measurements, topography, surface roughness, microstructure and quality of the samples were studied. No melting or debris was noticed in the case of nanosecond laser, while resolidified polymer debris was found around the machined grooves at pico- and femtosecond laser cases. However, debris formation was noticed to be less when increasing the scanning times leading smoother and much cleaner machined area. Profile measurements revealed that increasing scanning times lead to deeper grooves. Nano- and femtosecond laser machined grooves were deeper than picosecond laser machined ones due to the greater number of scanning times. In composites, active compounds were much more clearly seen in the case of nano- and femtosecond laser machining compared with picosecond laser machined grooves. Nanosecond laser machined grooves had sharp edges whereas the grooves of femtosecond laser were slightly tapered. In addition, SEM-pictures of picosecond laser machined grooves showed that using lower repetition rates no overlapping between laser pulses was found. On the other hand, materials started to melt when increasing the repetition rate.