Dr. Markus Kogel-Hollacher Profile

Dr. Markus Kogel-Hollacher

Director of R&D Projects at Precitec GmbH & Co KG

SPIE Involvement:

Conference Program Committee | Author

Publications (16)

Proceedings Article | 12 March 2024 Presentation + Paper

Meeting the challenges in e-mobility with laser welding and sophisticated system technology

Markus Kogel-Hollacher, Jens Reiser, Thomas Nicolay, Joachim Schwarz

Proceedings Volume 12873, 128730P (2024) https://doi.org/10.1117/12.3004992

KEYWORDS: Batteries, Laser welding, Laser processing, Industrial applications, Sensors, Industry, Ice, Artificial intelligence, Sensor technology, Process control

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Proceedings Article | 4 October 2023 Presentation + Paper

Industrial solution for 12-in. wafer high speed quality inspection: FSS 310

M. Kogel-Hollacher, S. Weiss, S. Mieth, O. Schulz

Proceedings Volume 12684, 1268408 (2023) https://doi.org/10.1117/12.2675224

KEYWORDS: Semiconducting wafers, Sensors, Scanners, Inspection, Information technology, Distance measurement, Coating thickness, Semiconductors

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Proceedings Article | 20 September 2023 Paper

Interferometric surface inspection with movable measurement spot: high-speed OCT imaging for thickness and topography in industry

M. Kogel-Hollacher, T. Nicolay, S. Mieth, Jens Reiser

Proceedings Volume 12607, 1260702 (2023) https://doi.org/10.1117/12.3005058

KEYWORDS: Sensors, Inspection, Scanners, Interferometry, Head, Information technology, Industry, Optical coherence tomography, Mirrors, Distance measurement

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The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology. Complete 3D measurement of objects using white light interference in mass production is time consuming and therefore not well-suited for use as a means of inline inspection. In addition, the long measurement cycles with complex sequences generate large amounts of data and the effort for processing the data must also be included in overall considerations. The Flying Spot Scanner (FSS) intelligently avoids these disadvantages and is therefore ideal for inline inspections. To meet the need of additional, even complex and time sensitive measurement tasks, Precitec Optronik has developed the Flying Spot Sensor. The active measuring head was specially developed for in-line use and ideally complements the spectral interferometric sensor to form a smart inspection system. The light from the sensor is coupled into the measuring head via a light guide and deflected by a mirror system, a so-called galvanometer scanner. Finally, the light passes through a telecentric lens, which serves as a focusing module on the outward path and as a measuring aperture for the reflected light. Due to the movable mirror system, the measuring light beam can be deflected at different angles and thus the measuring spot can be freely positioned within the field of view of the lens. Long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring, or scanning time. By using specialize focusing modules, the Flying Spot Scanner can be adapted to different application scenarios. These optics are characterized by a low curvature of the focal plane, very small telecentric errors and a very large depth of field. The measurement system can also be used in two operating modes, a thickness mode, or a distance mode. The two operating modes can be selected at will via the digital interface, which means that the switching process can be easily integrated into an automatic measuring sequence.

Proceedings Article | 15 March 2023 Presentation + Paper

Quality and physical properties revealed: sensors for monitoring and controlling laser processes in combination with sophisticated data models

Markus Kogel-Hollacher, Jens Reiser, Sebastian Moser, Fabian Mack, Joachim Schwarz

Proceedings Volume 12414, 1241409 (2023) https://doi.org/10.1117/12.2646187

KEYWORDS: Machine learning, Batteries, Laser processing, Artificial intelligence, Data modeling, Sensors, Process control, Data processing, Signal processing, Materials properties, Sensor technology

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There are many distinct commercial sensor systems for monitoring or controlling laser processes. Most of them are based on camera or photodiode technology. Furthermore, the introduction of real in-process measuring systems in laser material processing like OCT has significantly increased the safety of both defect detection and process control [5][6][7][8][9]. The focus of this contribution, however, relates to the use of artificial intelligence algorithms to "See New Things". We will discuss how classified, physical properties can be derived from already reliable process information - "seeing the unseen", so to speak. Instead of defining complex rules for algorithms, the use of Data Science and Machine Learning methods reveals hidden structures in noisy unstructured data and make it possible to find the relationships of the data to the physical measurement. There are several systems available in the market which capture or measure and analyze physical effects of the process zone and their properties during the laser processing, but none of these effects and properties stand for “seam quality” for themselves, which is typically defined by mechanical, geometrical and metallurgical properties of the solidified seam. The process properties like emitted visible and thermal radiation or geometrical values of the melt pool or the penetration depth of the laser forming the keyhole (penetration depth) only provide indications of how the desired quality might be achieved. When welding thousands of seams per shift during serial production for Li-Ion batteries in e-mobiles, very often users would like to stop their fully automatic machines once the laser process is suddenly running out of previously set boundaries. Such an approach allows users to find systematic faults where and when they occur, rather than at the end of the line where quality inspection takes place and the line is still running, producing more and more parts with the same faults. When it comes to the use of artificial intelligence algorithms the following questions must be answered: ▪ Is it possible to map an input time series to a real value? ▪ Can we get out the strength of the weld from the process emissions? ▪ Is the information buried in the signal? The vision, which can be represented by Figure 1, is that by using the data from process emissions and specific data models, a relationship to physical quantities can be established. Thus, AI goes a significant step beyond the simple "good-bad" statement.

Proceedings Article | 30 September 2022 Presentation + Paper

Flying spot scanner: high-speed OCT imaging for thickness and topography in industry

M. Kogel-Hollacher, T. Nicolay, S. Mieth

Proceedings Volume 12231, 1223102 (2022) https://doi.org/10.1117/12.2633987

KEYWORDS: Sensors, Scanners, Inspection, Interferometry, Distance measurement, Information technology, Optical coherence tomography, Mirrors, Time metrology

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The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology. Precitec Optronik is developing since decades intelligent sensor systems based on chromatic confocal or interferometric measurement principle. To meet the need of additional, even complex and time sensitive measurement tasks, Precitec Optronik has developed the Flying Spot Sensor. The active measuring head was specially developed for in-line use and ideally complements the spectral interferometric sensor to form a smart inspection system. The light from the sensor is coupled into the measuring head via a light guide and deflected by a mirror system, a so-called galvanometer scanner. Finally, the light passes through a telecentric lens, which serves as a focusing module on the outward path and as a measuring aperture for the reflected light. Due to the movable mirror system, the measuring light beam can be deflected at different angles and thus the measuring spot can be freely positioned within the field of view of the lens. Long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring, or scanning time. By using specialize focusing modules, the Flying Spot Scanner can be adapted to different application scenarios. These optics are characterized by a low curvature of the focal plane, very small telecentric errors and a very large depth of field. The measurement system can also be used in two operating modes, a thickness mode, or a distance mode. The two operating modes can be selected at will via the digital interface, which means that the switching process can be easily integrated into an automatic measuring sequence.

Proceedings Article | 1 April 2022 Presentation

Non-symmetrical beam shaping for high-power laser cutting processes

Matthieu Meunier, Gwenn Pallier, Jannik Lind, Avinash Kumar, Markus Kogel-Hollacher, Pu Jian, Guillaume Labroille

Proceedings Volume PC11994, PC1199402 (2022) https://doi.org/10.1117/12.2614698

KEYWORDS: Laser cutting, Beam shaping, Laser processing, High power lasers, X-rays, X-ray imaging, Solid state lasers, Reflectivity, Optical fibers, Metals

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Proceedings Article | 4 March 2022 Presentation + Paper

The potential of photonic technologies in battery production: measurement, monitoring, control

Markus Kogel-Hollacher, Thomas Nicolay

Proceedings Volume 11994, 1199406 (2022) https://doi.org/10.1117/12.2605976

KEYWORDS: Sensor technology, Laser welding, Copper, Photons, Optical coherence tomography, Process control, Manufacturing, Laser processing, Global Positioning System, Aluminum

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Proceedings Article | 5 March 2021 Presentation

Laser based direct energy deposition with co-axial wire support and OCT sensor

Markus Kogel-Hollacher, Frédéric Adam, Christian Staudenmaier, Rüdiger Moser, Steffen Boley

Proceedings Volume 11679, 1167904 (2021) https://doi.org/10.1117/12.2576402

KEYWORDS: Sensors, Optical coherence tomography, Metals, Laser energy, Process control, Sensor technology, Sensor performance, Robotic systems, Printing

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Proceedings Article | 2 March 2020 Paper

OCT sensor for layer height control in DED using SINUMERIK® controller

Markus Kogel-Hollacher, Matthias Strebel, Christian Staudenmaier, Heinz-Ingo Schneider, Daniel Regulin

Proceedings Volume 11271, 112710O (2020) https://doi.org/10.1117/12.2540167

KEYWORDS: Sensors, Optical coherence tomography, Laser welding, Distance measurement, Laser processing, Interferometry, Laser applications, Head, Light sources, Additive manufacturing, Materials processing, Laser optics, Laser systems engineering, 3D printing

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Proceedings Article | 9 September 2019 Paper

The next level: high-speed controlled conformal coating processes and topology measurements

M. Kogel-Hollacher, J. Schulze, D. Schröder, T. Beck, M. Holzapfel

Proceedings Volume 11107, 111070L (2019) https://doi.org/10.1117/12.2527756

KEYWORDS: Coating, Inspection, Process control, Sensors, Interferometry, Sensor technology, Luminescence, Manufacturing, Dielectrics, Scanners

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Proceedings Article | 27 February 2019 Presentation + Paper

New horizons in laser material processing: how OCT sets new standards

Markus Kogel-Hollacher, Stephan André, Tobias Beck

Proceedings Volume 10911, 109110F (2019) https://doi.org/10.1117/12.2516967

KEYWORDS: Sensors, Laser processing, Optical coherence tomography, Laser welding, Distance measurement, Laser applications, Process control, Interferometry, Head, Light sources, 3D printing

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Proceedings Article | 18 August 2018 Paper

Low-coherence interferometry in laser processing: a new sensor approach heading for industrial applications

Markus Kogel-Hollacher, Stephan André, Tobias Beck

Proceedings Volume 10749, 1074912 (2018) https://doi.org/10.1117/12.2501295

KEYWORDS: Sensors, Laser welding, Laser processing, Interferometry, Distance measurement, Process control, Signal processing, Laser applications, Light sources, Head

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Proceedings Article | 15 February 2018 Paper

New milestones in laser cutting for quality improvement and process automation

Markus Kogel-Hollacher, Andreas Rudolf, Jan Heyrick

Proceedings Volume 10525, 105250F (2018) https://doi.org/10.1117/12.2311407

KEYWORDS: Cutting equipment, Process control, Laser cutting, Sensors, Gas lasers, Laser sources, Disk lasers, Lasers, Optical simulations, Laser processing, Optical fibers

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Proceedings Article | 19 April 2017 Presentation

Inline measurement for quality control from macro to micro laser applications (Conference Presentation)

Markus Kogel-Hollacher, Martin Schoenleber, Jochen Schulze, Thibault Bautze, Matthias Strebel, Rüdiger Moser

Proceedings Volume 10097, 1009707 (2017) https://doi.org/10.1117/12.2249676

KEYWORDS: Laser therapeutics, Research facilities, Control systems, Manufacturing, Process control, Laser applications, Sensors, Laser welding, Laser processing, Quality measurement

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The essential basis for a reliable and target-aimed process control is the understanding of the interaction between the laser beam and the treated material and this was gained by thorough research on the influence of the process input parameters on the interaction sub processes and on the treatment result. The main players con-ducting this research over the decades have been research facilities and institutes and this research is still in progress. Since the moment when it was possible to achieve the necessary power density to start the process of deep penetration welding, accompanied by a keyhole, there is hope - and need - to measure e.g. the depth of this vapor channel. In the decades in which the technology of deep penetration welding has been used, various approaches have been developed that allow a measurement of the depth of the keyhole. The aim of this contribution is to show a compact overview on the different approaches to monitor and/or control micro and macro laser welding processes and especially bring out those which successfully have been transferred from laboratory to serial production in the recent past and will be in the near future. Laser materials processing in general offers several possibilities for process monitoring systems or process control but the complexity of the process itself, meaning the dependence of the processing result on several process input parameters, does not facilitate their use. As only continuous supervision of the manufacturing process can guarantee the high demands on the quality of the produced parts, process monitoring systems have become more and more standardized devices in laser applications. There is no doubt that the basis for reliable on-line process monitoring systems is the possibility to measure significant indicators, which demonstrates the instantaneous condition of the interaction zone and/or neighboring areas. This contribution to the Photonics West 2017 LASE conference on the one hand will demonstrate an approach using chromatic coded line sensors for post-weld inspection, on the other hand will show a sensor, based on interferometric principle, which is capable to in-situ measure keyhole depth during deep penetration laser welding and further potential of this sensor approach.

Proceedings Article | 20 February 2017 Presentation + Paper

Inline measurement for quality control from macro to micro laser applications

Markus Kogel-Hollacher, Martin Schoenleber, Jochen Schulze, Jean Francois Pichot

Proceedings Volume 10091, 100910H (2017) https://doi.org/10.1117/12.2255824

KEYWORDS: Process control, Laser processing, Sensors, Laser applications, Laser welding, Quality measurement, Surface roughness, Control systems, Distance measurement, Signal processing, Interferometry, Light sources, Head

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Proceedings Article | 18 March 2016 Paper

Inline monitoring of laser processing: new industrial results with the low coherence interferometry sensor approach

Markus Kogel-Hollacher, Martin Schoenleber, Thibault Bautze, Rüdiger Moser, Matthias Strebel

Proceedings Volume 9741, 97410R (2016) https://doi.org/10.1117/12.2208004

KEYWORDS: Laser processing, Sensors, Laser welding, Interferometry, Capillaries, Laser applications, Process control, High power lasers, Temporal resolution, 3D acquisition, Distance measurement, Signal processing, Sensor technology, Optical filters

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Showing 5 of 16 publications

Conference Committee Involvement (7)

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XIV

25 January 2025 | San Francisco, California, United States

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XIII

31 January 2024 | San Francisco, California, United States

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XII

1 February 2023 | San Francisco, California, United States

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems XI

26 January 2022 | San Francisco, California, United States

High-Power Laser Materials Processing: Applications, Diagnostics, and Systems X

6 March 2021 | Online Only, California, United States

Showing 5 of 7 Conference Committees

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