Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Please note that all times are shown in the time zone of the conference. The current conference time is: 4th Aug 2021, 01:15:36am CEST

Program for LiM 2021
Process Innovations
Wednesday, 23/June/2021:
11:15am - 12:30pm

Session Chair: Prof. Jean Pierre Bergmann, Technische Universität Ilmenau, Germany
Location: Room 5

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11:15am - 11:30am

Study of pointing stabilization unit for femtosecond fiber beam delivery system

Benoit Beaudou1, Pierre guay1, Fetah Benabid1, Ivan Gusachenko2, Clément Jacquard2, Gwenn Pallier2, Guillaume Labroille2

1GLOphotonics; 2Cailabs

Recent development of hollow-core inhibited coupling fibres paves the way to fibre beam delivery for femtosecond laser manufacturing applications. Nevertheless, reaching sufficient quality and reliability for such a functionality in industrial environment requires a Laser-fiber coupling system immunes to thermal and vibration fluctuations. As the Microstructure hollow-core fiber damage threshold is dependent of beam pointing stability of the laser system, beam stabilization sub-system has to be implemented to insure stable operation. This study attempts to qualify two beam stabilisation systems. The first one is two piezo motors coupled with Four quadrant detectors. The second one is Cailabs’ all-optical mode-cleaner system based Multi-Plane Light Conversion (MPLC) technology. MPLC enables a high control of modes propagation: a misaligned beam is projected on an adapted mode basis and the unwanted energy is then dumped. To do such output fibre transmission efficiency and beam quality are investigated under controlled fluctuation of beam pointing.

11:30am - 11:45am

Superimposed beam deflection using acousto-optical deflectors in combination with a galvanometer scanner

Daniel Franz1, Gian-Luca Roth1, Stefan Rung1, Cemal Esen2, Ralf Hellmann1

1Applied Laser and Photonics Group, University of Applied Sciences Aschaffenburg, 63739 Aschaffenburg,Germany; 2Applied Laser Technologies, Ruhr-University Bochum, 44801 Bochum, Germany

We report on the deflection behavior of a combined scanning system consisting of two acousto-optical deflectors (AOD) and a galvanometer scanner for ultra-short laser pulses. Firstly, the dynamic behavior and the precision of the individual AOD subsystem are characterized within it’s deflection range at different positioning frequencies. For the combined scanning system the roundness of the focus spot within an AOD scan field and the scan field dimensions at different galvanometer deflections are analyzed. In addition, the roundness of the spot and the scan field dimensions are determined as a function of galvanometer deflection and focus level. The investigations show that focus spot roundness’s > 90 % in a z-range of 200 µm can be realized in a galvanometer scanning field of 30 x 30 mm with positioning frequencies of up to 1 MHz using the superimposed laser beam deflection, highlighting it´s great potential for highly dynamic laser micromachining.

11:45am - 12:00pm

Advanced quasi-simultaneous welding – a new approach to laser welding of polymers

Lea Sauerwein, René Geiger, Christian Ebenhöh

Evosys Laser GmbH, Germany

Evosys Laser GmbH is developing a new variant of laser plastic welding, the so called Advanced Quasi-Simultaneous Welding (AQW). It combines two monochromatic laser beam sources and wavelengths in a sequential time pattern. By using two different wavelengths in a quasi-simultaneous welding process, the specific deposition of radiation energy and heat into each joining partner can be better controlled. This results into a more reliable welding operation with an enlarged process window.

Trials employing the new AQW process show that a significant improvement in weld seam quality is possible compared to the standard process with only one laser source. Due to the wavelength of the secondary laser source, more energy is deposited in the transmissive joining partner. The increased volume of plasticized material in this part is leading to an increased weld strength. Furthermore, it facilitates processing high-performance thermoplastics which often impose challenges to the laser welding process.

12:00pm - 12:15pm

Fully reflective annular laser beam shaping for laser beam welding at 16kW

Matthieu Meunier1, Romain Cornee2, Aymeric Lucas1, David Lemaitre2, Pierre Vernaz-Gris1, Gwenn Pallier1, Eric Laurensot2, Olivier Pinel1

1Cailabs, France; 2Institut Maupertuis, France

Laser Beam Welding (LBW) is commonly used in many fields of the industry, ranging from automotive and naval to aerospace. In order to improve LBW performance (process speed and quality as well as thickness of the parts to be weld) handling higher power, shaping the laser beam and reducing the focus shift are key.

We describe here a beam shaper compatible with industry standard equipment. The fully reflective design ease the heat evacuation leading to a reduced focus shift thanks to the absence of thermal gradient inside the optics, leading to better beam stability and process.

We demonstrate here the system capability to shape the input beam into an annular shape of high quality. The process tests are performed at multi-kW level up to 16kW with a high stability over the whole process. The process test results and the weld quality improvements are described for different materials.

12:15pm - 12:30pm

Laser-based manufacturing of ceramic matrix composites

Willy Kunz1, Clemens Steinborn1, Stefan Polenz2, Benjamin Braun3, Alexander Michaelis1

1Fraunhofer IKTS, Germany; 2Fraunhofer IWS, Germany; 3Space Structures GmbH, Germany

Ceramic matrix composites (CMCs) are quasi-ductile ceramics with excellent high-temperature properties. The main area of application is in aircraft engines as a replacement for nickel-based superalloys. Besides the high cost of the fiber material, the production of CMCs is quite expensive as advanced furnace technology is required. Furthermore, the joining of CMC components is still insufficiently developed.

This paper presents a novel manufacturing process that uses a laser as a heat source to locally solidify the ceramic material by generating a transient liquid matrix phase. Material properties as well as microstructural investigations are shown. The process is classified with regard to potential areas of application.

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