{ "types" : { "Bookmark" : { "pluralLabel" : "Bookmarks" }, "Publication" : { "pluralLabel" : "Publications" }, "GoldStandardPublication" : { "pluralLabel" : "GoldStandardPublications" }, "GoldStandardBookmark" : { "pluralLabel" : "GoldStandardBookmarks" }, "Tag" : { "pluralLabel" : "Tags" }, "User" : { "pluralLabel" : "Users" }, "Group" : { "pluralLabel" : "Groups" }, "Sphere" : { "pluralLabel" : "Spheres" } }, "properties" : { "count" : { "valueType" : "number" }, "date" : { "valueType" : "date" }, "changeDate" : { "valueType" : "date" }, "url" : { "valueType" : "url" }, "id" : { "valueType" : "url" }, "tags" : { "valueType" : "item" }, "user" : { "valueType" : "item" } }, "items" : [ { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/26a3fd12e7c8e11c15501269b170a2747/annefeuer", "tags" : [ "drilling","laser","micromaterialprocessing","modeling","myown","steel","ultrashortpulse" ], "intraHash" : "6a3fd12e7c8e11c15501269b170a2747", "interHash" : "a08ac59aa54c2255a5516691af9ec8bd", "label" : "Quality Aspects in Percussion Drilling with Ultrashort Laser Pulses", "user" : "annefeuer", "description" : "Invited talk", "date" : "2021-09-13 12:57:55", "changeDate" : "2021-09-13 10:57:55", "count" : 2, "pub-type": "presentation", "year": "2021", "url": "", "author": [ "Anne Feuer","Rudolf Weber","David Brinkmeier","Thomas Graf" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "David", "last" : "Brinkmeier"}, {"first" : "Thomas", "last" : "Graf"} ], "editor": [ "Anne Feuer" ], "editors": [ {"first" : "Anne", "last" : "Feuer"} ], "abstract": "Percussion drilling with ultrashort laser pulses is often associated with a poor quality of the exit of the microholes. Therefore, complex drilling methods such as helical drilling must often be used to achieve high-quality holes. However, it is not yet fully clarified why helical drilling produces significantly better results in terms of microhole exit than percussion drilling. Therefore, the emergence and change of quality of the exit of percussion-drilled holes during the drilling process was studied in detail. For the quantitative analysis of the quality of the microhole exit, microscope images were evaluated using a machine learning approach. By comparing theoretical and experimental results, it was possible to derive conditions under which high-quality exits can be produced with simple percussion drilling. The fluence at the exit of the microholes during the drilling process was found as a decisive influencing variable defining the quality of the microhole exit. In the current talk, the experimental and theoretical investigations are presented, whereby the focus will be on the influence of laser fluence on the edge quality of percussion-drilled microholes. It will be shown that the quality of the exits of percussion-drilled microholes can be significantly improved if the fluence dependence is correctly considered.", "venue" : "virtual", "language" : "English", "eventdate" : "October 18-20th, 2021", "eventtitle" : "ICALEO 2021", "bibtexKey": "feuer.2021.quality" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2d2013e1ae78b414d18487dc317dc4d2c/annefeuer", "tags" : [ "drilling","laser","micromaterialprocessing","modeling","myown","steel","ultrashortpulse" ], "intraHash" : "d2013e1ae78b414d18487dc317dc4d2c", "interHash" : "cfe881de56302af14cf6566da62f9c03", "label" : "Fluence dependence of the edge quality of microhole exits for percussion drilling with ultrashort laser pulses", "user" : "annefeuer", "description" : "", "date" : "2021-09-13 11:38:47", "changeDate" : "2021-09-13 10:29:37", "count" : 2, "pub-type": "inproceedings", "booktitle": "Proceedings of the Lasers in Manufacturing Conference 2021","publisher":"German Scientific Laser Society (WLT e.V.)", "year": "2021", "url": "", "author": [ "Anne Feuer","Rudolf Weber","Thomas Graf" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "Thomas", "last" : "Graf"} ], "editor": [ "Anne Feuer" ], "editors": [ {"first" : "Anne", "last" : "Feuer"} ], "abstract": "For many applications, edge quality and shape accuracy of microholes are crucial. One assumption is that the fluence at the tip of the microhole during drilling is a key parameter for the quality of the microhole\u2019s exit. It was therefore investigated experimentally how the fluence affects the edge quality. The experiments were performed in 0.5 mm thick steel using a Ti: sapphire laser system operating at a wavelength of 800 nm, a pulse duration of 1 ps, and a repetition rate of 1 kHz. For the quantitative analysis of the edge quality, microscope images were evaluated using a machine learning approach. Two key figures, striations amplitude and perimeter ratio, were defined that proved to be significant in characterizing the edge quality of exits. In the current talk it will be shown that the quality of exits of percussion-drilled microholes could be significantly improved if the fluence dependence is considered.", "eventtitle" : "Lasers in Manufacturing Conference 2021 (LiM)", "language" : "English", "eventdate" : "June 21 - 24, 2021", "bibtexKey": "feuer.2021.fluence" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/261cdb9c772f761119a637c1c5c3103b0/annefeuer", "tags" : [ "drilling","laser","micromaterialprocessing","modeling","myown","peer","steel","ultrashortpulse" ], "intraHash" : "61cdb9c772f761119a637c1c5c3103b0", "interHash" : "4c695c21806aec1e9dd2f140a1a6ec07", "label" : "High\u2011quality percussion drilling with ultrashort laser pulses", "user" : "annefeuer", "description" : "", "date" : "2021-09-13 11:14:12", "changeDate" : "2021-09-13 10:40:19", "count" : 4, "pub-type": "article", "journal": "Appl Phys A (Applied Physics A)", "year": "2021", "url": "https://rdcu.be/ctXIe", "author": [ "Anne Feuer","Rudolf Weber","Ronny Feuer","David Brinkmeier","Thomas Graf" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "Ronny", "last" : "Feuer"}, {"first" : "David", "last" : "Brinkmeier"}, {"first" : "Thomas", "last" : "Graf"} ], "editor": [ "Anne Feuer" ], "editors": [ {"first" : "Anne", "last" : "Feuer"} ], "volume": "127:665","number": "9","pages": "1-9","abstract": "The influence of the laser fluence on the quality of percussion-drilled holes was investigated both experimentally and by an analytical model. The study reveals that the edge quality of the drilled microholes depends on the laser fluence reaching the rear exit of the hole and changes with the number of pulses applied after breakthrough. The minimum fluence that must reach the hole\u2019s exit in order to obtain high-quality microholes in stainless steel was experimentally found to be 2.8 times the ablation threshold.", "language" : "English", "doi" : "https://doi.org/10.1007/s00339-021-04818-w", "bibtexKey": "feuer.2021.highquality" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2a5c12b656ab54bc6fe70dc9815fafa39/annefeuer", "tags" : [ "Drilling","Laser","MicroMaterialProcessing","Steel","UltrashortPulse","myown" ], "intraHash" : "a5c12b656ab54bc6fe70dc9815fafa39", "interHash" : "43e757b2ef681e2a1eb0c7fcd432512f", "label" : "Depth and quality limit for percussion-drilled microholes with depth > 1 mm using ultrashort pulsed laser radiation", "user" : "annefeuer", "description" : "", "date" : "2021-06-09 10:00:24", "changeDate" : "2021-09-13 10:29:05", "count" : 3, "pub-type": "inproceedings", "booktitle": "Proceedings of the Lasers in Manufacturing Conference 2019","publisher":"German Scientific Laser Society (WLT e.V.)", "year": "2019", "url": "https://www.wlt.de/lim/Proceedings2019/data/PDF/Contribution_349_final.pdf", "author": [ "Anne Feuer","Daniel J. Förster","Rudolf Weber","Thomas Graf" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Daniel J.", "last" : "Förster"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "Thomas", "last" : "Graf"} ], "abstract": "Based on the assumption that laser-drilled microholes can be approximated by a cone the maximum depth as a function of the laser fluence can be predicted by a simple analytical model. In this contribution, it will be shown, that the calculated maximum depth agrees well to microholes in stainless steel with drilling depth > 1mm. A Ti: sapphire laser at a wavelength of 800 nm and a pulse duration of 1 ps was used to percussion drill microholes with pulse energies up to 5 mJ and the corresponding maximum drilling depth was determined. Due to the low repetition rate of 1 kHz heat accumulation effects could be excluded. Furthermore, the quality of the microhole exit was investigated as a function of the peak fluence in 1 mm stainless steel, including the formation of side channels and the development of the shape of the microhole exit.", "eventtitle" : "Lasers in Manufacturing Conference 2019", "venue" : "Munich, Germany", "eventdate" : "June 2019", "bibtexKey": "feuer.2019.depth" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/27e13cdbedf9ca093a254ca61c43d473e/annefeuer", "tags" : [ "Drilling","Laser","MicroMaterialProcessing","Steel","UltrashortPulse","myown" ], "intraHash" : "7e13cdbedf9ca093a254ca61c43d473e", "interHash" : "bd30ce0c642f9ee35fcdddbadbc41147", "label" : "Influence of laser parameters on quality of microholes and process efficiency", "user" : "annefeuer", "description" : "", "date" : "2021-06-09 08:59:03", "changeDate" : "2021-06-09 08:02:19", "count" : 4, "pub-type": "inproceedings", "booktitle": "Laser Applications in Microelectronic and Optoelectronic Manufacturing (LAMOM) XIX","series": "Proc. SPIE", "year": "2014", "url": "https://doi.org/10.1117/12.2037674", "author": [ "Anne Feuer","Christoph Kunz","Martin Kraus","Volkher Onuseit","Rudolf Weber","Thomas Graf","Denis Ingildeev","Frank Hermanutz" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Christoph", "last" : "Kunz"}, {"first" : "Martin", "last" : "Kraus"}, {"first" : "Volkher", "last" : "Onuseit"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "Thomas", "last" : "Graf"}, {"first" : "Denis", "last" : "Ingildeev"}, {"first" : "Frank", "last" : "Hermanutz"} ], "volume": "89670H","abstract": "To enable the direct-spinning process of super-micro fibres (< 0.5 dtex) suitable for novel medical, hygienical and technical products microhole arrays with diameters down to 25 μm in very high quality are required. Using ultrashort pulses together with a helical drilling optics microholes with high accuracy were manufactured in metals of a thickness in the range of 0.3 mm. However, the required process time for a single microhole ranges up to several ten seconds. Simple energy balance considerations show that higher averaged powers - either achieved with larger pulse energies or\r\nan increased repetition rate - considerable reduce the process time. In this case plasma formation and heat accumulation\r\nshow an increased formation of melt and recast. Thus, the objective is to increase the productivity while maintaining consistent quality of the microholes.\r\nWith this aim, the influence of pulse energy and repetition rate on the borehole geometry, processing quality and process efficiency was investigated for helical drilling. In the present research work a TruMicro 5250 laser source (tp = 8 ps, λ=515 nm, fR=800 kHz) was used. To determine the process time of the microhole the transmitted laser radiation was recorded. A systematic evaluation of the process quality and process time dependent on pulse energy and repetition rate will be presented in this contribution. First laser manufactured spinning nozzles with microhole diameters down to 25 μm processed in 0.24 mm thick AuPt alloy were used to fabricate unique super-micro fibres with yarn counts down to 0.2 dtex.", "venue" : "San Francisco, California, United States", "language" : "English", "eventdate" : "1-6 February 2014", "eventtitle" : "SPIE LASE, Photonics West", "doi" : "10.1117/12.2037674", "bibtexKey": "Feuer.2014.Influence" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2df932f657ef68f0240a29e8b4ea5a8b3/annefeuer", "tags" : [ "BeamShaping","Cutting","Glass","Laser","MicroMaterialProcessing","MultipassAmplifier","UltraShortPulse","myown","peer" ], "intraHash" : "df932f657ef68f0240a29e8b4ea5a8b3", "interHash" : "e85fb7ca2f342577640e92fb87f836bb", "label" : "Single-pass laser separation of 8 mm thick glass with a millijoule picosecond pulsed Gaussian\u2013Bessel beam", "user" : "annefeuer", "description" : "", "date" : "2019-04-18 14:04:52", "changeDate" : "2019-04-18 12:04:52", "count" : 3, "pub-type": "article", "journal": "Journal of Applied Physics", "year": "2019", "url": "", "author": [ "Anne Feuer","Jens-Ulrich Thomas","Christian Freitag","Rudolf Weber","Thomas Graf" ], "authors": [ {"first" : "Anne", "last" : "Feuer"}, {"first" : "Jens-Ulrich", "last" : "Thomas"}, {"first" : "Christian", "last" : "Freitag"}, {"first" : "Rudolf", "last" : "Weber"}, {"first" : "Thomas", "last" : "Graf"} ], "editor": [ "Anne Feuer" ], "editors": [ {"first" : "Anne", "last" : "Feuer"} ], "volume": "125","number": "5","pages": "213","abstract": "Efficient micromachining of glass with thicknesses of up to several millimeters can be enabled by using picosecond laser pulses with energies in the order of millijoules. In the experiments presented in this article, we investigated in-volume modifications in different thicknesses of borosilicate and soda lime glass using an axicon-generated Gaussian\u2013Bessel beam. The main objective of the study was to demonstrate the separation of 8 mm thick soda lime glass within a single pass of the laser beam.", "language" : "englisch", "doi" : "https://doi.org/10.1007/s00339-019-2624-7", "bibtexKey": "Feuer.2019.Single-pass" } ] }