TY - CHAP A1 - Maiwald, Frederik A1 - Tröger, Johannes A1 - Hierl, Stefan T1 - Automated weld seam evaluation and 2D simulation parameter calibration for absorber-free laser transmission welding T2 - Lasers in Manufacturing Conference (LIM 2023), 26. Juni bis 29. Juni 2023, München N2 - Absorber-free laser transmission welding enables clean and precise joining of plastics without additives or adhesives. It is therefore well suited to produce optical and medical devices, which place high demands on cleanliness and accuracy. However, the weld usually has an undesirably large vertical expansion, causing bulges and distortion. To improve this, the intensity distribution of the laser beam as well as the processing strategy must be adapted. Due to the complexity, this is aided by process simulation. However, simulation parameter calibration and verification are usually done considering the seam width and height, which is of limited significance. To overcome this, we propose a new method for image processing of microtome sections, determining the spatially resolved geometry of the weld. Thus, the deviation between experiment and simulation can be calculated pixel by pixel. This spatially resolved value is predestined for the calibration of the simulation parameters: For a parameter field with 18 different settings, the total deviation between experiment and simulation is less than 11 % after calibration. KW - plastics welding KW - image processing KW - simulation KW - optimization Y1 - 2023 UR - https://www.wlt.de/sites/default/files/2023-09/Contribution_122.pdf PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik e.V. (WLT) ER - TY - GEN A1 - Käsbauer, Johannes A1 - Schmailzl, Anton A1 - Hierl, Stefan ED - Klippel, Clemens ED - Mottok, Jürgen ED - Reichenberger, Marcus T1 - Simulative investigation on the influence of material- and process parameter on quasi-simultaneous laser transmission welding BT - Poster Session T2 - Applied Research Conference - ARC 2017, 7 July 2017 München Y1 - 2017 PB - pro Business GmbH CY - Berlin ER - TY - GEN A1 - Schmailzl, Anton A1 - Hierl, Stefan ED - CADFEM GmbH, ED - ANSYS Germany GmbH, T1 - FE-Modellbildung der Strahl-Stoff-Wechselwirkung beim Laser-Durchstrahlschweißen in ANSYS 14.0 T2 - ANSYS Conference & 32th CADFEM Users' Meeting 2014, 04.-06. Juni, Nürnberg Y1 - 2014 N1 - DVD-ROM SP - 1 EP - 15 CY - Grafing bei München ER - TY - GEN A1 - Armbruster, Dominik ED - Mottok, Jürgen ED - Reichenberger, Marcus ED - Scharfenberg, Georg ED - Ziemann, Olaf T1 - Optimization of a system technology for coaxial online pyrometry in three-dimensional laser transmission welding BT - Poster Session T2 - Applied Research Conference 2015 ARC 2015 ; 3rd July 2015 Nürnberg Y1 - 2015 SP - 314 EP - 317 PB - pro Business GmbH CY - Berlin ER - TY - GEN A1 - Maiwald, Frederik A1 - Schmailzl, Anton A1 - Hierl, Stefan ED - Klippel, Clemens ED - Mottok, Jürgen ED - Reichenberger, Marcus T1 - Thermo-mechanical computation of weld seam geometry in laser transmission welding BT - Poster Session T2 - Applied Research Conference - ARC 2017, 7 July 2017, München Y1 - 2017 PB - pro Business GmbH CY - Berlin ER - TY - GEN A1 - Meisner, Dennis A1 - Kaftiranis, Nikitas A1 - Maiwald, Frederik A1 - Rapp, Petra A1 - Hierl, Stefan T1 - Enhancing Layer Adhesion in Material Extrusion AM with Adaptive Laser Preheating Integrated in Printhead T2 - LiM Conference 2025, Lasers in Manufacturing, June 23 - 26, 2025, Munich, Germany N2 - Material extrusion is a widely used AM process and is gaining more acceptance in industry applications due to its material variety, flexibility, and low cost. However, its usage is limited by a process-related anisotropy caused by insufficient interlayer bonding due to reduced temperature in the process zone. To enhance layer adhesion, an adaptive laser preheating system is integrated in a conventional printhead around the extrusion nozzle. The setup with eight fiber coupled diode laser allows preheating in feed direction and investigation of various intensity profiles. The article describes the experimental setup and significant improvements achieved. Laser preheating with different intensity distributions (spot, sickle or ring shaped) show an incasement of up to 85 % of the mechanical properties in the build-up direction. However, due to the additional energy input by the laser, controlled cooling of the workpiece becomes a crucial factor and is investigated as well. Y1 - 2025 UR - https://www.wlt.de/lim-conference PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik e.V. ER - TY - CHAP A1 - Schmailzl, Anton A1 - Steger, Sebastian A1 - Dostalek, Michael A1 - Hierl, Stefan ED - Klotzbach, U. ED - Washio, K. ED - Arnold, C. B. T1 - Online process monitoring at quasi-simultaneous laser transmission welding using a 3D-scanner with integrated pyrometer T2 - Proc. SPIE, Laser-based Micro- and Nanoprocessing X, SPIE LASE 2016, San Francisco, California, United States N2 - Quasi-simultaneous laser transmission welding is a well-known joining technique for thermoplastics and mainly used in the automotive as well as in the medical industry. For process control usually the so called set-path monitoring is used, where the weld is specified as "good" if the irradiation time is inside a defined confidence interval. However, the detection of small-sized gaps or thermal damaged zones is not possible with this technique. The analyzation of the weld seam temperature during welding offers the possibility to overcome this problem. In this approach a 3D-scanner is used instead of a scanner with flat-field optic. By using a pyrometer in combination with a 3D-scanner no color-corrected optic is needed in order to provide that laser- and detection-spot are concentric. Experimental studies on polyethylene T-joints have shown that the quality of the signal is adequate, despite the use of an optical setup with a long working distance and a small optical aperture. The effects on temperature are studied for defects like a gap in the joining zone. Therefore a notch was milled into the absorbent polymer. In case of producing housings for electronic parts the effect of an electrical wire between the joining partners is also investigated. Both defects can be identified by a local temperature deviation even at a feed rate of four meters per second. Furthermore a strategy for signal-processing is demonstrated. By this, remaining defects can be identified. Consequently an online detection of local defects is possible, which makes a dynamic process control feasible. KW - Defect detection KW - Fiber lasers KW - Laser ablation KW - Laser processing KW - Laser welding KW - Mirrors KW - Process control KW - Pyrometry KW - Scanners KW - Signal processing KW - Temperature metrology KW - Polymers Y1 - 2016 U6 - https://doi.org/10.1117/12.2211705 IS - 97361J SP - 1 EP - 7 ER - TY - CHAP A1 - Schmailzl, Anton A1 - Hierl, Stefan ED - CADFEM GmbH, ED - ANSYS Germany GmbH, T1 - Rechenzeitoptimierte Temperaturfeldberechnung beim quasisimultanen Laser-Durchstrahlschweißen T2 - ANSYS Conference & 33. CADFEM Users' Meeting 2015, 24.-26. Juni 2015, Bremen, Germany N2 - Beim quasisimultanen Laser-Durchstrahlschweißen von Kunststoffen wird bisher die FEM-Simulation wegen der Vielzahl von Umläufen des Laserstrahls und der damit verbundenen hohen Rechenzeit kaum eingesetzt. Um die Temperaturfeldberechnung zur Prozessauslegung und -optimierung praktikabel nutzen zu können, ist eine Reduktion der Rechenzeit zwingend erforderlich. Zur Simulation von Schweißvorgängen in ANSYS-CLASSIC werden die thermischen Lasten mithilfe von Ersatzwärmequellen auf Basis von APDL-Routinen berechnet. Im Gegensatz dazu wird in dieser Arbeit eine analytische Lastfunktion zur Berechnung der thermischen Last für das quasismultane Laser-Durchstrahlschweißen vorgestellt. Im Vergleich zur Temperaturfeldberechnung mit Ersatzwärmequelle kann bei der Berechnung eines dreidimensionalen Modells die Rechenzeit von mehreren Wochen auf wenige Stunden und für ein zweidimensionales auf nur wenige Minuten reduziert werden. Y1 - 2015 UR - http://www.cae-wiki.info/wikiplus/images/6/6a/UM2015-2.04.03.pdf N1 - DVD-ROM SP - 1 EP - 15 CY - Grafing bei München ER - TY - RPRT A1 - Steger, Sebastian A1 - Schmailzl, Anton A1 - Dostalek, Michael A1 - Armbruster, Dominik A1 - Hierl, Stefan ED - Baier, Wolfgang T1 - Entwicklung einer Systemtechnik für das quasisimultane Laser-Durchstrahlschweißen von 3D-Kunststoffbauteilen mit Temperaturmessung und Spanndruckregelung T2 - OTH Forschungsbericht 2016 Y1 - 2016 UR - https://doi.org/10.35096/othr/pub-1384 SP - 37 EP - 38 PB - Inixmedia GmbH CY - Kiel ER - TY - CHAP A1 - Schmailzl, Anton A1 - Armbruster, Dominik A1 - Dostalek, Michael A1 - Steger, Sebastian A1 - Hierl, Stefan ED - Falter, Thomas T1 - Strahlführungs- und -formungskonzept zur koaxialen Temperaturmessung beim scanner-basierten Laser-Durchstrahlschweißen T2 - 2. OTH-Clusterkonferenz, 18. Januar 2017, Techbase, Regensburg, Tagungsband Y1 - 2016 SP - 201 EP - 204 PB - Weber Druck CY - Regensburg ER -