Product Code: ICA11_M503

Stability Limits of Laser Drilled Hole Arrays On Large Areas
Authors:
Nelli Hambach, Fraunhofer Institute for Laser Technology ILT; Aachen Germany
Claudia Hartmann, Fraunhofer Institute for Laser Technology ILT; Aachen Germany
Jens Holtkamp, Fraunhofer Institute for Laser Technology ILT; Aachen Germany
Arnold Gillner, Fraunhofer Institute for Laser Technology ILT; Aachen Germany
Presented at ICALEO 2011

Large area micro drilling utilizing short pulsed solid state lasers is becoming an important manufacturing technique in the filtration technology. High transmittance and quality of the drilled holes are the main challenges. Roundness and diameter variation of the holes is understood as the holes quality. High transmittance can be achieved with uniform-sized and large holes and a small pitch. The resulting effects and stability limits of the percussion drilling process using ns pulsed laser source with a wavelength of 355 nm and 50 µm thin Aluminum foil are investigated in this paper. Different drilling strategies are tested in relation on heat propagation, hole diameter and roundness. The quality of drilled holes decreases with decreasing pitch and hole diameter because of increasing thermal and laser source pointing stability effects. Either effects are directional and can be superposed. A positive superposition of the effects decreases the drilled hole quality, whereat a negative superposition can even eliminate the effects and increase the quality.