Femtosecond fiber laser welding of PMMA

Abstract

Femtosecond-pulsed laser welding of transparent materials on a micrometer scale is a versatile tool for the fabrication and assembly of electronic, electromechanical, and especially biomedical micro-devices. In this paper, we report on microwelding of two transparent layers of polymethyl methacrylate (PMMA) with femtosecond laser pulses at 1030 nm in the MHz regime. We aim at exploiting localized heat accumulation to weld the two layers without any preprocessing of the sample and any intermediate absorbing media, by focusing fs-laser pulses at the interface. The modifications produced by the focused laser beam into the bulk material have been firstly investigated depending on the laser process parameters aiming to produce continuous melting. Results have been evaluated based on heat accumulation models. Finally, fs-laser welding of PMMA samples have been successfully demonstrated and tested by leakage tests for application in direct laser assembly of microfluidic devices.

One-Step Femtosecond Laser Stealth Dicing of Quartz

“…At an even higher repetition rate of 100 kHz, the laser induced crack propagation mechanism is no longer under control, owing to the excessive thermal load released into the focal volume [39]. This causes significant collateral damage around the laser absorption area, with unacceptable quality of the cut edges, as shown in Figure 2 c,d.…”

Laser turning of PMMA with ultrashort laser pulses using UV and IR

“…The use of focused, ultrashort laser pulses for the conventional machining of polymeric materials is well established. Processes for micro hole drilling [2][3][4], welding [5][6][7] and surface structuring [8][9][10][11] are commonly applied. Also, selective material modifications to generate, e.g., internal micro channels or the alteration of the refractive index for photonic applications such as polymer optical waveguides and Bragg gratings are subject to intense research [12][13][14][15][16][17][18] The process of tangential laser turning, however, is yet to be investigated thoroughly.…”