{"fb9869432d270933b8cde8271ac7f8d8michaelsawannia":{"DOI":"10.1007/s40516-025-00324-6","ISBN":"","ISSN":"2196-7237","URL":"https://doi.org/10.1007/s40516-025-00324-6","abstract":"Simulations of laser cutting need experimental measurements of the cutting front geometry and its temperature for validation purposes. A combined polarization goniometer and quotient pyrometer was used to measure these values for a cut in 10 mm stainless steel using a framerate of 75 kHz and a spatial resolution of 36 $\\mu$m. For the first time, synchronized geometric and temperature measurements are given for a laser cutting front. These measurements show that, for 1 $\\mu$m wavelength laser cutting of stainless steel, one of the main mechanisms of thermal and material flow involves the movement of hot `humps' of liquid down the cutting front. These mobile humps experience an enhanced absorption of laser radiation on their upper surface and a reduced absorbed power density on their lower part, and may even cast a shadow on the cut front immediately below them. In this work, these phenomena resulted in local temperature fluctuations of 800 K, including temperature drops to 200 K below the melting temperature for durations of up to approximately 200 µs.","annote":"","author":[{"family":"Sawannia","given":"Michael"},{"family":"Powell","given":"John"},{"family":"Borkmann","given":"Madlen"},{"family":"Hagenlocher","given":"Christian"},{"family":"Graf","given":"Thomas"}],"citation-label":"Sawannia2025","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Lasers in Manufacturing and Materials Processing","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2025","nov","28"]],"literal":"2025"},"event-place":"","id":"fb9869432d270933b8cde8271ac7f8d8michaelsawannia","interhash":"e5a5d76013c488a38e18ff4c2080ae23","intrahash":"fb9869432d270933b8cde8271ac7f8d8","issue":"","issued":{"date-parts":[["2025","nov","28"]],"literal":"2025"},"keyword":"cutting goniometer laser myown peer pyrometer","misc":{"issn":"2196-7237","doi":"10.1007/s40516-025-00324-6"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Laser Cutting; Experimental Measurement of Fluctuations in Cut Front Temperature and Morphology","type":"article-journal","username":"michaelsawannia","version":"","volume":""},"fb9869432d270933b8cde8271ac7f8d8ifsw":{"DOI":"10.1007/s40516-025-00324-6","ISBN":"","ISSN":"2196-7237","URL":"https://doi.org/10.1007/s40516-025-00324-6","abstract":"Simulations of laser cutting need experimental measurements of the cutting front geometry and its temperature for validation purposes. A combined polarization goniometer and quotient pyrometer was used to measure these values for a cut in 10 mm stainless steel using a framerate of 75 kHz and a spatial resolution of 36 $\\mu$m. For the first time, synchronized geometric and temperature measurements are given for a laser cutting front. These measurements show that, for 1 $\\mu$m wavelength laser cutting of stainless steel, one of the main mechanisms of thermal and material flow involves the movement of hot `humps' of liquid down the cutting front. These mobile humps experience an enhanced absorption of laser radiation on their upper surface and a reduced absorbed power density on their lower part, and may even cast a shadow on the cut front immediately below them. In this work, these phenomena resulted in local temperature fluctuations of 800 K, including temperature drops to 200 K below the melting temperature for durations of up to approximately 200 µs.","annote":"","author":[{"family":"Sawannia","given":"Michael"},{"family":"Powell","given":"John"},{"family":"Borkmann","given":"Madlen"},{"family":"Hagenlocher","given":"Christian"},{"family":"Graf","given":"Thomas"}],"citation-label":"Sawannia2025","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Lasers in Manufacturing and Materials Processing","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2025","nov","28"]],"literal":"2025"},"event-place":"","id":"fb9869432d270933b8cde8271ac7f8d8ifsw","interhash":"e5a5d76013c488a38e18ff4c2080ae23","intrahash":"fb9869432d270933b8cde8271ac7f8d8","issue":"","issued":{"date-parts":[["2025","nov","28"]],"literal":"2025"},"keyword":"myown laser peer cutting pyrometer goniometer","misc":{"issn":"2196-7237","doi":"10.1007/s40516-025-00324-6"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Laser Cutting; Experimental Measurement of Fluctuations in Cut Front Temperature and Morphology","type":"article-journal","username":"ifsw","version":"","volume":""},"1b35cfad9aaf6fa8f6a54a2dc774f836dtraunecker":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"Due to the increasing variety of products and the demand for a sustainable production, flexible production systems are required that can work productively and sustainably from batch-size 1 onwards. This requires flexible and in-process capable quality assurance of the processes to be able to detect defective parts as soon as possible.\r\nOne important quality feature is the hardness, which can be affected during laser beam welding of metals. Usually, the hardness has to be determined post-process, often requiring destructive testing, which is unwanted for small batch sizes and a sustainable use of resources. Therefore, this contribution presents a method for the spatially resolved in-process determination of the hardness. \r\nThe resulting hardness depends on the cooling rate of the solidified metal during the process [1], and this relation was utilized for the in-process determination of the hardness. The cooling process, in turn, can be described by the heat loss coefficient which can be used as a simplified measure of the cooling rate. Therefore, the cooling curves were determined spatially resolved during the welding process using a scanning pyrometer, and the corresponding heat loss coefficients were determined from these cooling curves. Trials with different process parameters were carried out to investigate the correlation between the heat loss coefficient and the hardness, which was determined post-process with indentation measurements. The results show a correlation between the heat loss coefficient and the measured hardness with higher values of the heat loss coefficient coinciding with higher hardness values for each parameter set. Therefore, using the heat loss coefficient proved to be a promising approach for an in-process determination of the local hardness during laser welding of steel.","annote":"","author":[{"family":"Traunecker","given":"David"},{"family":"Jarwitz","given":"Michael"},{"family":"Graf","given":"Thomas"},{"family":"Michalowski","given":"Andreas"}],"citation-label":"traunecker2023inprocess","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2023"]],"literal":"2023"},"event-place":"","id":"1b35cfad9aaf6fa8f6a54a2dc774f836dtraunecker","interhash":"79ec335cd4437d845d148345c5b8f959","intrahash":"1b35cfad9aaf6fa8f6a54a2dc774f836","issue":"","issued":{"date-parts":[["2023"]],"literal":"2023"},"keyword":"diagnostics hardening laser myown processmonitoring pyrometer steel welding ybyag","misc":{"eventtitle":"International Conference on Advanced Joining Processes","venue":"Braga, Portugal","language":"englisch","eventdate":"19. – 20. Oktober 2023"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"In-process determination of the local hardness during laser beam welding of steel","type":"speech","username":"dtraunecker","version":"","volume":""},"1b35cfad9aaf6fa8f6a54a2dc774f836ifsw":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"Due to the increasing variety of products and the demand for a sustainable production, flexible production systems are required that can work productively and sustainably from batch-size 1 onwards. This requires flexible and in-process capable quality assurance of the processes to be able to detect defective parts as soon as possible.\r\nOne important quality feature is the hardness, which can be affected during laser beam welding of metals. Usually, the hardness has to be determined post-process, often requiring destructive testing, which is unwanted for small batch sizes and a sustainable use of resources. Therefore, this contribution presents a method for the spatially resolved in-process determination of the hardness. \r\nThe resulting hardness depends on the cooling rate of the solidified metal during the process [1], and this relation was utilized for the in-process determination of the hardness. The cooling process, in turn, can be described by the heat loss coefficient which can be used as a simplified measure of the cooling rate. Therefore, the cooling curves were determined spatially resolved during the welding process using a scanning pyrometer, and the corresponding heat loss coefficients were determined from these cooling curves. Trials with different process parameters were carried out to investigate the correlation between the heat loss coefficient and the hardness, which was determined post-process with indentation measurements. The results show a correlation between the heat loss coefficient and the measured hardness with higher values of the heat loss coefficient coinciding with higher hardness values for each parameter set. Therefore, using the heat loss coefficient proved to be a promising approach for an in-process determination of the local hardness during laser welding of steel.","annote":"","author":[{"family":"Traunecker","given":"David"},{"family":"Jarwitz","given":"Michael"},{"family":"Graf","given":"Thomas"},{"family":"Michalowski","given":"Andreas"}],"citation-label":"traunecker2023inprocess","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2023"]],"literal":"2023"},"event-place":"","id":"1b35cfad9aaf6fa8f6a54a2dc774f836ifsw","interhash":"79ec335cd4437d845d148345c5b8f959","intrahash":"1b35cfad9aaf6fa8f6a54a2dc774f836","issue":"","issued":{"date-parts":[["2023"]],"literal":"2023"},"keyword":"steel hardening myown ybyag welding diagnostics laser processmonitoring pyrometer","misc":{"eventtitle":"International Conference on Advanced Joining Processes","venue":"Braga, Portugal","language":"englisch","eventdate":"19. – 20. Oktober 2023"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"In-process determination of the local hardness during laser beam welding of steel","type":"speech","username":"ifsw","version":"","volume":""},"3c8df5a1fe0b88ea8d7061cf332c904adtraunecker":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"Due to the increasing product variety, flexible production facilities are required that can already work productively from batch-size 1 onwards. This requires flexible and online-capable quality assurance of the processes to be able to detect defective parts as soon as possible. One important quality feature in laser welding is the resulting hardness, which usually must be determined post-process. In this paper, a method for the spatially resolved online determination of the hardness is presented at the example of laser welding of mild steel. The dependence of the hardness on the cooling rate was utilized for this purpose. Therefore, the cooling curves were determined spatially resolved during the welding process using a scanning pyrometer and the heat loss coefficient was determined from these cooling curves as a measure of the cooling rate. The corresponding local hardness was determined post-process. The results show a correlation between the local hardness values and the local heat loss coefficients within a set of process parameters, making this a promising approach for the spatially resolved online determination of the hardness.","annote":"","author":[{"family":"Traunecker","given":"David"},{"family":"Jarwitz","given":"Michael"},{"family":"Michalowski","given":"Andreas"},{"family":"Graf","given":"Thomas"}],"citation-label":"traunecker2023online","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2023"]],"literal":"2023"},"event-place":"","id":"3c8df5a1fe0b88ea8d7061cf332c904adtraunecker","interhash":"dd1713d591de18da325a26e53a9764e6","intrahash":"3c8df5a1fe0b88ea8d7061cf332c904a","issue":"","issued":{"date-parts":[["2023"]],"literal":"2023"},"keyword":"diagnostics hardening laser myown processmonitoring pyrometer steel welding ybyag","misc":{"eventtitle":"Lasers in Manufacturing","venue":"Munich, Germany","language":"englisch","eventdate":"26. – 29. Juni 2023"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Online determination of the local hardness during laser beam welding of steel","type":"speech","username":"dtraunecker","version":"","volume":""},"3c8df5a1fe0b88ea8d7061cf332c904aifsw":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"Due to the increasing product variety, flexible production facilities are required that can already work productively from batch-size 1 onwards. This requires flexible and online-capable quality assurance of the processes to be able to detect defective parts as soon as possible. One important quality feature in laser welding is the resulting hardness, which usually must be determined post-process. In this paper, a method for the spatially resolved online determination of the hardness is presented at the example of laser welding of mild steel. The dependence of the hardness on the cooling rate was utilized for this purpose. Therefore, the cooling curves were determined spatially resolved during the welding process using a scanning pyrometer and the heat loss coefficient was determined from these cooling curves as a measure of the cooling rate. The corresponding local hardness was determined post-process. The results show a correlation between the local hardness values and the local heat loss coefficients within a set of process parameters, making this a promising approach for the spatially resolved online determination of the hardness.","annote":"","author":[{"family":"Traunecker","given":"David"},{"family":"Jarwitz","given":"Michael"},{"family":"Michalowski","given":"Andreas"},{"family":"Graf","given":"Thomas"}],"citation-label":"traunecker2023online","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2023"]],"literal":"2023"},"event-place":"","id":"3c8df5a1fe0b88ea8d7061cf332c904aifsw","interhash":"dd1713d591de18da325a26e53a9764e6","intrahash":"3c8df5a1fe0b88ea8d7061cf332c904a","issue":"","issued":{"date-parts":[["2023"]],"literal":"2023"},"keyword":"steel hardening myown ybyag welding diagnostics laser processmonitoring pyrometer","misc":{"eventtitle":"Lasers in Manufacturing","venue":"Munich, Germany","language":"englisch","eventdate":"26. – 29. Juni 2023"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Online determination of the local hardness during laser beam welding of steel","type":"speech","username":"ifsw","version":"","volume":""},"efeacfdc1a73c303f047d84a396532d3dtraunecker":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"Due to the increasing product variety, flexible production facilities are required that can already work productively from\r\nbatch-size 1 onwards. This requires flexible and online-capable quality assurance of the processes to be able to detect\r\ndefective parts as soon as possible.\r\nOne important quality feature in laser welding is the resulting hardness, which usually must be determined post-process.\r\nIn this paper, a method for the spatially resolved online determination of the hardness is presented at the example of\r\nlaser welding of mild steel. The dependence of the hardness on the cooling rate was utilized for this purpose.\r\nTherefore, the cooling curves were determined spatially resolved during the welding process using a scanning pyrometer\r\nand the heat loss coefficient was determined from these cooling curves as a measure of the cooling rate. The\r\ncorresponding local hardness was determined post-process. The results show a correlation between the local hardness\r\nvalues and the local heat loss coefficients within a set of process parameters, making this a promising approach for the\r\nspatially resolved online determination of the hardness.","annote":"","author":[{"family":"Traunecker","given":"David"},{"family":"Jarwitz","given":"Michael"},{"family":"Michalowski","given":"Andreas"},{"family":"Graf","given":"Thomas"}],"citation-label":"david2023online","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2023"]],"literal":"2023"},"event-place":"","id":"efeacfdc1a73c303f047d84a396532d3dtraunecker","interhash":"dd1713d591de18da325a26e53a9764e6","intrahash":"efeacfdc1a73c303f047d84a396532d3","issue":"","issued":{"date-parts":[["2023"]],"literal":"2023"},"keyword":"Diagnostics Hardening Laser ProcessMonitoring Pyrometer Steel Welding YbYAG myown","misc":{"eventtitle":"Lasers in Manufacturing","venue":"Munich, Germany","language":"englisch","eventdate":"26. – 29. Juni 2023"},"note":"","number":"","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Online determination of the local hardness during laser beam\r\nwelding of steel","type":"paper-conference","username":"dtraunecker","version":"","volume":""},"625783871231bd75192c739fe06feffamichaelsawannia":{"DOI":"","ISBN":"","ISSN":"","URL":"https://www.schweissenundschneiden.de/ausgaben/ausgabe-1-2022","abstract":"","annote":"","author":[{"family":"Reisgen","given":"Uwe"},{"family":"Olschock","given":"Simon"},{"family":"Engels","given":"Oliver"},{"family":"Graf","given":"Thomas"},{"family":"Weber","given":"Rudolf"},{"family":"Sawannia","given":"Michael"},{"family":"Jarwitz","given":"Michael"}],"citation-label":"Sawannia.2022.Zeitlich.und.örtlich","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Schweissen und Schneiden","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2022"]],"literal":"2022"},"event-place":"","id":"625783871231bd75192c739fe06feffamichaelsawannia","interhash":"19bb1c9756e312f4e0b300bd4f5d5abb","intrahash":"625783871231bd75192c739fe06feffa","issue":"","issued":{"date-parts":[["2022"]],"literal":"2022"},"keyword":"ProcessMonitoring Pyrometer SurfaceTreatment laser myown","misc":{"language":"Deutsch"},"note":"","number":"","number-of-pages":"7","page":"24-31","page-first":"24","publisher":"","publisher-place":"","status":"","title":"Zeitlich und örtlich geregelte Temperaturfelder bei der Werkstoffbearbeitung mit dem Elektronenstrahl und dem Laserstrahl","type":"article-journal","username":"michaelsawannia","version":"","volume":"1"},"625783871231bd75192c739fe06feffaifsw":{"DOI":"","ISBN":"","ISSN":"","URL":"https://www.schweissenundschneiden.de/ausgaben/ausgabe-1-2022","abstract":"","annote":"","author":[{"family":"Reisgen","given":"Uwe"},{"family":"Olschock","given":"Simon"},{"family":"Engels","given":"Oliver"},{"family":"Graf","given":"Thomas"},{"family":"Weber","given":"Rudolf"},{"family":"Sawannia","given":"Michael"},{"family":"Jarwitz","given":"Michael"}],"citation-label":"Sawannia.2022.Zeitlich.und.örtlich","collection-editor":[],"collection-title":"","container-author":[],"container-title":"Schweissen und Schneiden","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2022"]],"literal":"2022"},"event-place":"","id":"625783871231bd75192c739fe06feffaifsw","interhash":"19bb1c9756e312f4e0b300bd4f5d5abb","intrahash":"625783871231bd75192c739fe06feffa","issue":"","issued":{"date-parts":[["2022"]],"literal":"2022"},"keyword":"myown Pyrometer from:michaelsawannia ProcessMonitoring laser SurfaceTreatment","misc":{"language":"Deutsch"},"note":"","number":"","number-of-pages":"7","page":"24-31","page-first":"24","publisher":"","publisher-place":"","status":"","title":"Zeitlich und örtlich geregelte Temperaturfelder bei der Werkstoffbearbeitung mit dem Elektronenstrahl und dem Laserstrahl","type":"article-journal","username":"ifsw","version":"","volume":"1"},"e59ae3898eb0693efa37433797e7f92eflorianfetzer":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"","annote":"","author":[{"family":"Roeder","given":"S."}],"citation-label":"Roeder.2000.Transmissionseigenschaften","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2000","jun"]],"literal":"2000"},"event-place":"","genre":"Master thesis","id":"e59ae3898eb0693efa37433797e7f92eflorianfetzer","interhash":"0edaa49fbefa29966d16d7fcfeefe100","intrahash":"e59ae3898eb0693efa37433797e7f92e","issue":"IFSW00-16","issued":{"date-parts":[["2000","jun"]],"literal":"2000"},"keyword":"Laser OpticalElements Pyrometer Seibold,Gabi Studienarbeit","note":"","number":"IFSW00-16","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Transmissionseigenschaften einer Optik zur Berücksichtigung bei pyrometrischen Temperaturmessungen","type":"thesis","username":"florianfetzer","version":"","volume":""},"e59ae3898eb0693efa37433797e7f92eifsw":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"","annote":"","author":[{"family":"Roeder","given":"S."}],"citation-label":"Roeder.2000.Transmissionseigenschaften","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2000","jun"]],"literal":"2000"},"event-place":"","genre":"Master thesis","id":"e59ae3898eb0693efa37433797e7f92eifsw","interhash":"0edaa49fbefa29966d16d7fcfeefe100","intrahash":"e59ae3898eb0693efa37433797e7f92e","issue":"IFSW00-16","issued":{"date-parts":[["2000","jun"]],"literal":"2000"},"keyword":"Studienarbeit Pyrometer Laser OpticalElements from:florianfetzer Seibold,Gabi","note":"","number":"IFSW00-16","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Transmissionseigenschaften einer Optik zur Berücksichtigung bei pyrometrischen Temperaturmessungen","type":"thesis","username":"ifsw","version":"","volume":""},"4874d444dc6dccdac118cf00be0a5384florianfetzer":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"","annote":"","author":[{"family":"Krüger","given":"P."}],"citation-label":"Krüger.2012.Temperaturmessung","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2012","may"]],"literal":"2012"},"event-place":"","genre":"Master thesis","id":"4874d444dc6dccdac118cf00be0a5384florianfetzer","interhash":"5040dd537572bddcfacd3fafa26d1024","intrahash":"4874d444dc6dccdac118cf00be0a5384","issue":"IFSW12-09","issued":{"date-parts":[["2012","may"]],"literal":"2012"},"keyword":"Diplomarbeit Laser ProcessDevelopment Pyrometer Weberpals,Jan-Philipp","note":"","number":"IFSW12-09","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Temperaturmessung mittels Mehrwellenlängenpyrometrie","type":"thesis","username":"florianfetzer","version":"","volume":""},"4874d444dc6dccdac118cf00be0a5384ifsw":{"DOI":"","ISBN":"","ISSN":"","URL":"","abstract":"","annote":"","author":[{"family":"Krüger","given":"P."}],"citation-label":"Krüger.2012.Temperaturmessung","collection-editor":[],"collection-title":"","container-author":[],"container-title":"","documents":[],"edition":"","editor":[],"event-date":{"date-parts":[["2012","may"]],"literal":"2012"},"event-place":"","genre":"Master thesis","id":"4874d444dc6dccdac118cf00be0a5384ifsw","interhash":"5040dd537572bddcfacd3fafa26d1024","intrahash":"4874d444dc6dccdac118cf00be0a5384","issue":"IFSW12-09","issued":{"date-parts":[["2012","may"]],"literal":"2012"},"keyword":"Pyrometer Laser from:florianfetzer Weberpals,Jan-Philipp ProcessDevelopment Diplomarbeit","note":"","number":"IFSW12-09","page":"","page-first":"","publisher":"","publisher-place":"","status":"","title":"Temperaturmessung mittels Mehrwellenlängenpyrometrie","type":"thesis","username":"ifsw","version":"","volume":""}}