Absorber-free laser transmission welding of transparent polymers using fixed focus optics and 3D laser scanner

Maiwald, Frederik; Englmaier, Stephan; Hierl, Stefan

doi:10.1016/j.procir.2020.09.117

Cited by 2 publications

(3 citation statements)

References 7 publications

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“…It is moved by a 2-axis linear system enabling feed rates v of up to 300 mm/s. We have already presented a detailed description of the experimental setup, the processing parameters and the simulation-based process layout [14]. The samples are made of semi-crystalline polyamide 6 (Ultramid B3S) provided by BASF SE (Ludwigshafen am Rhein, Germany) and molded by Gerresheimer Regensburg GmbH (Regensburg, Germany) with a coefficient of absorption α of 0.8 1/mm at a wavelength of 1940 nm.…”

Section: Experimental Setup For Laser Transmission Weldingmentioning

confidence: 99%

“…Absorber-free laser transmission welding possesses several advantages (i.e., contactless input of energy, high precision, no adhesives and no particle formation) which enable the fulfilment of the aforementioned demands [1][2][3]. In contrast to conventional transparent-absorbent welding, where one partner contains a laser absorbent additive [2,4,5], or an additional absorbing material is placed in the joining zone [6][7][8][9], the samples analyzed in this work are made of identical polymers and were joined directly using absorber-free laser transmission welding [10][11][12][13][14][15][16]. Figure 1 shows the process principle of absorber-free laser transmission welding.…”

Section: Introductionmentioning

confidence: 99%

“…A laser beam with the wavelength in the polymers' intrinsic absorption spectrum between 1.6 µ m and 2 µ m is used. Focusing the beam with a comparably high numerical aperture (NA) provides significant intensity gradients inside the specimen, which enables the selective fusing of the joining zone [1,13,14]. The joining of two 1 mm thick partners with a 0.05 mm to 0.6 mm wide weld seam, for example, is possible without affecting the surface of the upper joining partner [11,14].…”

Section: Introductionmentioning

confidence: 99%

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Optical Coherence Tomography for 3D Weld Seam Localization in Absorber-Free Laser Transmission Welding

et al. 2022

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Quality and reliability are of the utmost importance for manufacturing in the optical and medical industries. Absorber-free laser transmission welding enables the precise joining of identical polymers without additives or adhesives and is well-suited to meet the demands of the aforementioned industries. To attain sufficient absorption of laser energy without absorbent additives, thulium fiber lasers, which emit in the polymers’ intrinsic absorption spectrum, are used. Focusing the laser beam with a high numerical aperture provides significant intensity gradients inside the workpiece and enables selective fusing of the internal joining zone without affecting the surface of the device. Because seam size and position are crucial, the high-quality requirements demand internal weld seam monitoring. In this work, we propose a novel method to determine weld seam location and size using optical coherence tomography. Changes in optical material properties because of melting and re-solidification during welding allow for weld seam differentiation from the injection-molded base material. Automatic processing of the optical coherence tomography data enables the identification and measurement of the weld seam geometry. The results from our technique are consistent with microscopic images of microtome sections and demonstrate that weld seam localization in polyamide 6 is possible with an accuracy better than a tenth of a millimeter.

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Section: Experimental Setup For Laser Transmission Weldingmentioning

confidence: 99%