Product Code: ICAL08_403

Micromachining of Glass with Short ns-Pulses and Highly Repetitive fs-Laser Pulses
Authors:
S. Mauersberger, University of Applied Sciences; Mittweida Germany
U. Loeschner, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
H. Exner, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
J. Schille, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
R. Ebert, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
P. Regenfuss, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
L. Hartwig, Hochschule Mittweida University of Applied Sciences; Mittweida Germany
Presented at ICALEO 2008

In this paper we are going to present first results on 3d laser micro cutting of glasses as a technology for rapid micro tooling, obtained at the laser institute of the University of Applied Sciences Mittweida. The investigations were carried out with a short pulse Nd:YAG slab laser of Edgewave (Aachen) and a high repetition rate fs-laser of Clark-MXR Inc. Michigan. In our experiments the laser beam was focussed onto the sample with both a transmitting achromatic objective and a laser scanner with an f-theta-objective combined with a high precision xyz-axis stage.
The technique utilizes nonlinear absorption effects to induce local heating, followed by stress generation and finally micro crack formation inside the transparent bulk material. A lot of side effects have to be considered in machining of transparent materials, for example, nonlinear processes like self focussing and the focal shift. In the beginning for various glasses the dependence of the micro crack formation on the process parameters were investigated in detail - possibilities and limits are discussed. The development of strategies of applicable arrangements of micro cracks to produce fracture lines, planes and shells enclosing the required component are object of our investigations in order to produce 3d micro parts. These components created with the presented technology are consisting of bulk material - the key benefit in comparison to laser micro sintered parts.