@article{57175,
  author       = {{Bathelt, Lukas and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  issn         = {{1877-0509}},
  journal      = {{Procedia Computer Science}},
  pages        = {{2018--2027}},
  publisher    = {{Elsevier BV}},
  title        = {{{Innovative measurement system for saber curvature observation in straightening processes}}},
  doi          = {{10.1016/j.procs.2024.02.024}},
  volume       = {{232}},
  year         = {{2024}},
}

@inproceedings{57174,
  abstract     = {{Increasing the sustainability and resource efficiency of forming processes is one of today's major goals. High-strength wire materials are usually available as strip material and are subjected to a downstream forming process such as punch-bending to produce parts for the electronics industry, for example. During the manufacturing process of the semi-finished product, residual stresses and plastic deformations are introduced into the wire by rolling and drawing processes. Straightening machines are used in the production lines to compensate for these. To increase the sustainability of these production lines, the straightening process is an essential step. Before the continuous manufacturing process starts, the straightening process must be set up and the optimal roller positions must be found. Once the process is set up, the roller position settings are usually not changed. Due to missing measurement systems for the straightening quality, it is not possible to dynamically adjust the positions of the straightening rollers to variations in the material properties. This leads to deviations in the dimensional accuracy of the components to be produced and thus to an increase in the rejection rate in the manufacturing processes. To reduce the rejection rate, a novel control system for a continuous feedback control of a straightening process is presented in this paper. This leads to a reduction of the rejection rate and unnecessary preforming operations in wire straightening process. The result is an increasing sustainability and efficiency of these production process.}},
  author       = {{Bathelt, Lukas and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Innovative control system for straightening machines using sensor information from downstream processes}}},
  doi          = {{10.21741/9781644903131-308}},
  volume       = {{41}},
  year         = {{2024}},
}

@inproceedings{57183,
  abstract     = {{In multi-stage bending and straightening operations cross-stage and quantity-dependent effects crucially affect the quality of the end product. Using punch-bending units in combination with a mechatronic straightening device can improve the accuracy and repeatability of product features remarkably well. In this work a concept for an innovative hybrid model of a roll straightener in a multi-stage straightening and multi-stage bending process is proposed. This model combines data-driven elements with expert knowledge and aims to minimise residual errors of the roll straightener to reliably decrease the risk of disadvantageous cross-stage and quantity-dependent effects on a subsequent punch-bending process.}},
  author       = {{Peters, Henning and Djakow, Eugen and Rostek, Tim and Mazur, Andreas and Trächtler, Ansgar and Homberg, Werner and Hammer, Barbara}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Novel approach for data-driven modelling of multi-stage straightening and bending processes}}},
  doi          = {{10.21741/9781644903131-252}},
  volume       = {{41}},
  year         = {{2024}},
}

@article{48781,
  abstract     = {{In a punch-bending machine, wire products are manufactured for a wide range of industrial sectors, such as the electronics industry. The raw material for this process is flat wire made of high-strength steel. During the manufacturing process of the flat wire, residual stresses and plastic deformations are induced into the wire. These residual stresses and deformations fluctuate over the length of the semi-finished product and have a negative effect on the final product quality. Straightening machines are used to reduce this influence to a minimum. So far, the adjustment of a straightening machine has been performed manually, which is a lengthy and complex task even for an experienced worker. This inevitably leads to the use of inefficient straightening strategies and causes high rejection rates in the entire production process. Due to a lack of sensor information from the straightening operation, application of modern feedback control methods has not been practicable. This paper presents a novel design for a straightening machine with an integrated, precise straightening force measurement. By simultaneously monitoring the position of the straightening rollers, state variables of the straightening operation can be derived. Additionally, a tension control for feeding the flat wire is introduced. This is implemented to mitigate the disturbing effects caused by irregularities in the wire-feeding process. In the results of this article, the high precision of the developed force measurement design and its possible applications are shown.}},
  author       = {{Bathelt, Lukas and Scurk, Maximilian and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  issn         = {{1424-8220}},
  journal      = {{Sensors}},
  number       = {{22}},
  title        = {{{Novel Straightening-Machine Design with Integrated Force Measurement for Straightening of High-Strength Flat Wire}}},
  doi          = {{10.3390/s23229091}},
  volume       = {{23}},
  year         = {{2023}},
}

@inproceedings{48572,
  abstract     = {{<jats:p>Abstract. To increase the sustainability of forming processes such as punch bending, homogenization of the processed semi-finished product is an essential step in the manufacturing process. High-strength wire materials are usually available as strip material before being further processed in a forming process. For storage and transport, the material is coiled onto coils and transported to the customer. During the coiling process, residual stresses and plastic deformation are introduced into the wire. Thus, the final product quality is also influenced by the geometry of the coil. Straightening machines are used in production lines to compensate for these. Once a straightening machine has been set up, the settings for the roll positions are usually not changed. As a result, there is no reaction to material fluctuations, which means that the components to be produced do not meet the dimensional accuracy requirements. This leads to an increase in the rejection rate in manufacturing processes. To reduce the rejection rate, it is necessary to enable dynamic and flexible infeed of the straightening rollers. In this context, an innovative control concept with disturbance compensation was developed for the straightening process. The disturbance compensation uses a disturbance model that predicts the change in bending curvature over the coil radius. With this prediction, the straightening machine can be adjusted specifically. The roller positions are adjusted by a subordinate position control. The additional feedback from measured geometric product properties from the following punching-bending process enables the straightening machine to be adjusted even in the case of unforeseen fluctuations in the material properties. In this way, it is possible to react to any material fluctuations as required. This novel, demand-oriented adjustment of the straightening machine is expected to result in a high increase in the efficiency of the production process and a reduction of the rejection rate. </jats:p>}},
  author       = {{Bathelt, Lukas and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar}},
  booktitle    = {{Materials Research Proceedings}},
  issn         = {{2474-395X}},
  publisher    = {{Materials Research Forum LLC}},
  title        = {{{Innovative self-learning disturbance compensation for straightening processes}}},
  doi          = {{10.21741/9781644902479-216}},
  year         = {{2023}},
}

@inproceedings{48001,
  author       = {{Bathelt, Lukas and Djakow, Eugen and Dahms, Frederik and Henke, Christian and Trächtler, Ansgar and Homberg, Werner}},
  booktitle    = {{Ilmenauer Federntag 2023: Neueste Erkenntnisse zu Funktion, Berechnung, Prüfung und Gestaltung von Federn und Werkstoffen}},
  isbn         = {{978-3-948595-09-8}},
  location     = {{Ilmenau}},
  publisher    = {{ISLE Steuerungstechnik und Leistungselektronik}},
  title        = {{{Neuartiger Ansatz zum Richten von zwei- und dreidimensionalen Fehlern an einem Federdraht}}},
  year         = {{2023}},
}

@inproceedings{30263,
  abstract     = {{High-strength wire materials are usually available as strip material which is further processed in a forming process (e.g. punch-bending). For storage and transport of the semi-finished wire to the customer, the material is wound onto coils. The manufacturing and coiling process introduces plastic deformations into the wire, which lead to undesirable residual stresses and wire curvature of the semi-finished product. These residual stresses and curvatures cause variations in the material properties of the semi-finished product, which have a negative impact on the subsequent product quality. Straightening machines are used to compensate the residual stresses and the curvature in the wire. At the beginning of the straightening process, the straightening machines must be set up in such a way that residual stresses and curvatures are optimally compensated. This setup process is usually a manual and iterative process, where a lot of material is wasted until the optimal settings for the straightening machine are found.In order to reduce the amount of material waste, the operator must be supported in the setup process. In this context, a new and innovative setup assistance system was developed to support the operator during the setup process. The setup assistant system automatically detects the wire curvature by means of an optical measuring system. Based on the optically detected measuring points, the wire curvature is determined by a robust calculation algorithm. Based on a database built up through the carried out experimental and numerical research work, the optimum setting parameters for the straightening machine are suggested to the operator without lengthy trial and error. After confirmation by the operator, the roller settings are automatically adjusted by the mechatronic straightening machine. With the presented method, the conventional iterative setup procedure can be made more resource-efficient and a high straightening quality can be reproducibly achieved. }},
  author       = {{Bathelt, Lukas and Bader, Fabian and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar and Homberg, Werner}},
  location     = {{Braga / Portugal}},
  title        = {{{Innovative assistance system for setting up a mechatronic straightening machine}}},
  doi          = {{https://doi.org/10.4028/p-vs07w9}},
  year         = {{2022}},
}

@inproceedings{30265,
  abstract     = {{Due to increasing globalization and rising quality requirements, the steel and metal processing industry is facing growing cost and innovation pressure. Not least because of their high lightweight potential, high-strength steel materials are meeting the growing material requirements of steel and metal processing in areas such as aerospace and medical technology. In particular, the tight tolerance limits of applicable shape and dimensional accuracies pose a challenge in the processing of high-strength steel strip materials. Improving the processability of high-strength steel materials through the use of straighteners with set-up assistance systems significantly increases the potential for competing with other materials such as aluminum or magnesium alloys. }},
  author       = {{Bader, Fabian and Bathelt, Lukas and Djakow, Eugen and Henke, Christian and Homberg, Werner and Trächtler, Ansgar}},
  location     = {{Braga / Portugal}},
  title        = {{{An approach for an innovative 3d steel strip straightening machine for curvature and saber compensation}}},
  doi          = {{https://doi.org/10.4028/p-87wvu0}},
  year         = {{2022}},
}

@inproceedings{33978,
  author       = {{Bathelt, Lukas and Bader, Fabian and Djakow, Eugen and Henke, Christian and Trächtler, Ansgar and Homberg, Werner}},
  booktitle    = {{Fachtagung VDI MECHATRONIK 2022 }},
  location     = {{Darmstadt}},
  pages        = {{19--24}},
  title        = {{{Mechatronische Richtapparate: Intelligente Richttechnik von hochfesten Flachdrähten}}},
  year         = {{2022}},
}

@inproceedings{21447,
  abstract     = {{Even though the spectrum of parts is expected to shift over the long term as a result of increasing e-mobility, there is still an extremely high demand for complex components made of high-strength materials which can only be produced by hydroforming technologies. The innovative combination of hydroforming processes with other forming processes, as well as the improvement of the processes themselves, offers considerable potential for improvement. 
A number of promising ways of improving the hydroforming process chain are therefore the subject of this contribution. The focus of the article is on possible approaches for combining (incremental) pre- and post-forming operations, which can permit considerable improvements in both quality and features at a reduced cost. Furthermore, a novel combination of quasi-static and high-speed forming processes is presented, leading to an improved overall forming process (with a high application potential) for the production of complex parts. 
}},
  author       = {{Wiens, Eugen and Djakow, Eugen and Homberg, Werner}},
  booktitle    = {{Nebu/Nehy 2020}},
  keywords     = {{Hydroforming, Incremental Forming, Internal Flow-turning, High-speed Forming}},
  title        = {{{Some ideas for the further development of hydroforming process chains}}},
  year         = {{2020}},
}

@phdthesis{15030,
  abstract     = {{Working-media-based forming processes (WMBF) represent a great potential regarding the production of complex sheet-metal lightweight components with excellent surface quality, shape accuracy and dimensional stability. The working-media-based forming processes characterize the sheet-metal forming process, where the sheet metal blank is formed during the forming process by means of a (quasi-)static or dynamic working media pressure into a contouring forming tool. Although the WMBF offers improved utilization of the formability of the used materials compared to conventional sheet metal forming processes, there are limits in the production of complex deeper or sharp edged components with (quasi-)static and dynamic WMBF processes, which can not be overcome by using these methods alone. In order to overcome this, multi-level WMBF process sequences for components with spherical and stepped geometries are developed in this work. Here the developed strategies combine the advantages of (quasi-)static and dynamic WMBF processes. Furthermore, based on analytical, experimental and numerical investigations, innovative process management strategies were derived, which completely compensate the local wall thickness changes, make better use of existing material resources and thus enable the safe production of mentioned geometries.}},
  author       = {{Djakow, Eugen}},
  keywords     = {{High Speed Forming}},
  pages        = {{188}},
  publisher    = {{Shaker}},
  title        = {{{Ein Beitrag zur kombinierten (quasi-)statischen und dynamischen Umformung von blechförmigen Halbzeugen}}},
  doi          = {{ISBN 978-3-8440-6723-1}},
  year         = {{2019}},
}

@article{15031,
  author       = {{Linnemann, M. and Psyk, V. and Djakow, Eugen and Springer, R. and Homberg, W. and Landgrebe, D.}},
  issn         = {{2351-9789}},
  journal      = {{Procedia Manufacturing}},
  pages        = {{21--26}},
  title        = {{{High-Speed Incremental Forming – New Technologies For Flexible Production Of Sheet Metal Parts}}},
  doi          = {{10.1016/j.promfg.2018.12.038}},
  year         = {{2019}},
}

@article{15036,
  author       = {{Piper, M. and Zibart, A. and Djakow, Eugen and Springer, R. and Homberg, W. and Kenig, E.Y.}},
  issn         = {{1359-4311}},
  journal      = {{Applied Thermal Engineering}},
  pages        = {{142--146}},
  title        = {{{Heat transfer enhancement in pillow-plate heat exchangers with dimpled surfaces: A numerical study}}},
  doi          = {{10.1016/j.applthermaleng.2019.02.082}},
  year         = {{2019}},
}

@inproceedings{15032,
  author       = {{Spoelstra, Paul and Djakow, Eugen and Homberg, Werner}},
  title        = {{{Rubber pad forming - Efficient approach for the manufacturing of complex structured sheet metal blanks for food industry}}},
  doi          = {{10.1063/1.5008084}},
  year         = {{2017}},
}

@inproceedings{15033,
  author       = {{Djakow, Eugen and Springer, Robert and Homberg, Werner and Piper, Mark and Tran, Julian and Zibart, Alexander and Kenig, Eugeny}},
  title        = {{{Incremental electrohydraulic forming - A new approach for the manufacture of structured multifunctional sheet metal blanks}}},
  doi          = {{10.1063/1.5008083}},
  year         = {{2017}},
}