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AISTech 2023 Iron and Steel Technology Conference and Exposition

作者： Rohrhofer, Andreas Aflenzer, Helmut Reindl, Thomas Primetals Technologies Austria GmbH Turmstraße 44 4031 Austria

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A process-reliable tailoring of subsurface properties during cryogenic turning using dynamic process control

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PRODUCTION ENGINEERING-RESEARCH AND DEVELOPMENT 2024年第2期18卷 233-251页

作者： Denkena, Berend Breidenstein, Bernd Maier, Hans Juergen Prasanthan, Vannila Fricke, Lara Vivian Zender, Felix Nguyen, Hai Nam Zwoch, Stefan Wichmann, Marcel Barton, Sebastian Leibniz Univ Hannover Inst Prod Engn & Machine Tools Univ 2 D-30823 Hannover Germany Leibniz Univ Hannover Univ 2 Inst Werkstoffkunde Mat Sci D-30823 Hannover Germany

Considering the current demands for resource conservation and energy efficiency, innovative machining concepts and increased process reliability have a significant role to play. A combination of martensitic hardening of the subsurface and near-net-shape manufacturing represent a great potential to produce components with wear-resistant subsurfaces in an energy- and time-saving way. Within the scope of the present study, the influence of cryogenic machining of metastable austenitic steel on the martensitic transformation and surface quality was investigated. Different cooling strategies were used. A soft sensor based on eddy current in-process measurements was used to determine and subsequently affect the martensitic transformation of the subsurface. The feed rate and component temperature were identified as significant factors influencing the martensitic transformation. However, a high feed rate leads to an increase in surface roughness, and thus to a reduction in component quality. For this reason, a roughing process for achieving maximum martensitic transformation was carried out first in the present study and then a reduction in the surface roughness by maintaining the martensitic subsurface content was aimed for by a subsequent finishing process. With the knowledge generated, a dynamic process control was finally set up for designing the turning process of a required subsurface condition and surface quality.

关键词： Cryogenic turning Subsurface properties dynamic process control Deformation-induced martensitic transformation Eddy-current sensor

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A robust feeding strategy to maintain set-point glucose in mammalian fed-batch cultures when input parameters have a large error

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BIOTECHNOLOGY PROGRESS 2017年第2期33卷 317-336页

作者： Konakovsky, Viktor Clemens, Christoph Mueller, Markus Michael Bechmann, Jan Herwig, Christoph Vienna Univ Technol Inst Chem Engn Div Biochem Engn Gumpendorfer Str 1A 166-4 A-1060 Vienna Austria Boehringer Ingelheim Pharma GmbH & Co KG Dept Bioproc Dev Biberach Germany

Industrial CHO cell cultures run under fed-batch conditions are required to be controlled in particular ranges of glucose, while glucose is constantly consumed and must be replenished by a feed. The most appropriate feeding rate is ideally stoichiometric and adaptive in nature to balance the dynamically changing rate of glucose consumption. However, high errors in biomass and glucose estimation as well as limited knowledge of the true metabolic state challenge the control strategy. In this contribution, we take these errors into account and simulate the output with uncertainty trajectories in silico in order to control glucose concentration. Other than many control strategies, which require parameter estimation, our assumptions are founded on two pillars: (i) first principles and (ii) prior knowledge about the variability of fed-batch CHO cell culture. The algorithm was exposed to an in-silico Design of Experiments (DoE), in which variations of parameters were changed simultaneously, such as clone-specific behavior, precision of equipment and desired control range used. The results demonstrate that our method achieved the target of holding the glucose concentration within an acceptable range. A robust and sufficient level of control could be demonstrated even with high errors for biomass or metabolic state estimation. In a time where blockbuster drugs are queuing up for time slots of their production, this transferable control strategy that is independent of tedious establishment runs may be a decisive advantage for rapid implementation during technology transfer and scale up and decrease in campaign change over time. (c) 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:317-336, 2017

关键词： CHO cell culture fed-batch simulation dynamic process control uncertainty

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Run-to-run process control of a plasma etch process with neural network modelling

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QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL 1998年第4期14卷 247-260页

作者： Card, JP Naimo, M Ziminsky, W Digital Semicond Hudson MA 01749 USA

Run-to-run control of a plasma etch process for 8 inch diameter silicon wafers at Digital Semiconductor is determined by maintenance of targeted values of post-etch metrology variables. The post-etch quality variables are extremely sensitive to variation in the etch chamber conditions due to fluctuation in temperature, pressure, gas flow rates, etc., the aging of process tool parts and time since last chamber cleans. The target parameter drifts due to part wear and impurity build-up are long-term and distinct in character from the more immediate action of chamber parameter disturbance. We have modelled the multivariable and multimodal action of output etch parameter variation using a neural network prediction model coupled with an heuristic non-linear feedback loop to determine optimal corrective action to be performed between runs to ensure on-going etch tool control. The neural networks exhibited overall accuracy to within 20% of the observed values of 0.986, 0.938 and 0.87 for the post-etch rate, standard deviation and selectivity variables respectively. We present the neural model design with specially adapted input parameter transforms and results of training, test and validation sample fits for 148 monitor wafer records. The control unit was able to detect accurately the need for part replacements and wet clean operations in 34 of 40 operations and offered suggested process setting changes which were consistent with engineers' understanding of adjustments which would yield output parameters closer to the targeted values. Our current work extends previous modelling of the 6 inch wafer plasma etch process to 8 inch wafers with the addition of genetic algorithms for input variable selection and optimization algorithm improvements. In addition, we have installed a real-time shop floor data collection utility with extensive data quality assurance, enabling the controller to be implemented on a run-to-run basis with neural network updates between monitor etch runs.

关键词： neural network dynamic process control plasma etch semiconductor fabrication process control optimization integrated circuit semiconductor cascade correlation

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Measuring the accuracy of prediction in a simulated environment

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Simulation and Gaming 1998年第2期29卷 173-192页

作者： Mailles, Stéphanie Batatia, Hadj University of Mirail-Toulouse ARAMIIHS-IRI7 31062 Toulouse Cedex 4 118 route de Narbonne France Computer Architecture Research Group School of Science and Technology University of Teesside Middlesbrough TS 3BA Borough Road United Kingdom

Prediction is an important cognitive activity in any decision-making process. For dynamic process control tasks, this activity is crucial, but studying it in a real-life environment is difficult. This article describes how a computerized simulation was used to study prediction in a complex environment. Using the simulation, the effects of many factors on the accuracy of prediction were successfully measured. These factors are mainly the nature of the task the method of presentation of the information, the number of repetitions of a specific task, and the length of the time taken for prediction. Three different tasks and four distinct interfaces were used in the simulation. Prediction was found to be significantly affected by all of the factors except the number of repetitions. Surprisingly, no learning effect was observed throughout the accomplishment of the various tasks. © 1998 Sage Publications, Inc.

关键词： Computerized Simulation dynamic process control Information Presentation Prediction Work Complex Environments

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Q-REG+: The innovative approach to electrode regulation

Q-REG+: The innovative approach to electrode regulation

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AISTech 2015 Iron and Steel Technology Conference and 7th International Conference on the Science and Technology of Ironmaking, ICSTI 2015

作者： Onesti, D. Piazza, M. Ometto, M. Danieli Automation S.p.A. Via Bonaldo Stringher 4 Buttrio Italy

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UV-based dynamic control improves the robustness of multicolumn countercurrent solvent gradient purification of oligonucleotides

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BIOTECHNOLOGY JOURNAL 2024年第7期19卷 e2400170页

作者： Fioretti, Ismaele Mueller-Spath, Thomas Aumann, Lars Sponchioni, Mattia Politecn Milan Dept Chem Mat & Chem Engn Via Mancinelli 7 I-20131 Milan Italy YMC ChromaCon Zurich Switzerland

Therapeutic oligonucleotides (ONs) have great potential to treat many diseases due to their ability to regulate gene expression. However, the inefficiency of standard purification techniques to separate the target sequence from molecularly similar variants is hindering development of large scale ON manufacturing at a reasonable cost. Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) is a valuable process able to bypass the purity-yield tradeoff typical of single-column operations, and hence to make the ON production more sustainable from both an economic and environmental point of view. However, operating close to the optimum of MCSGP can be challenging, resulting in unstable process performance and in a drift in product quality, especially when running a continuous process for extended periods where process parameters such as temperature are prone to variation. In this work, we demonstrate how greater process robustness is introduced in the design and execution of MCSGP for the purification of a 20mer single-stranded DNA sequence through the implementation of UV-based dynamic control. With this novel approach, the cyclic steady state was reached already in the third cycle and disturbances coming from fluctuations in the feed quality, loading amount and temperature were effectively compensated allowing a stable operation close to the optimum. In response to the perturbations, the controlled process kept the standard deviation on product recovery below 3.4%, while for the non-controlled process it increased up to 27.5%. MCSGP is a twin-column chromatographic process able to by-pass the yield/purity tradeoff typical of single-column operations. In this work, the authors demonstrate the possibility of increasing the robustness of MCSGP through the design and implementation of UV-based dynamic process control, which automatically adjusts the duration of recycling and collection windows based on the UV chromatogram recorded online and user-defined UV thres

关键词： AutoPeak chromatography continuous chromatography countercurrent dynamic process control MCSGP oligonucleotides simulated moving bed

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Adaptive control for a dual laser beam solution for the welding of high reflectivity dissimilar materials

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Procedia CIRP 2022年 111卷 443-447页

作者： Beñat Arejita Juan Fernando Isaza Miguel Antunez Aitzol Zuloaga EXOM Engineering Avenida Altos Hornos de Vizcaya 33 Barakaldo 48901 Spain UPV/EHU Ingeniero Torres Quevedo Plaza 1 Bilbao 48013 Spain

The laser welding technology delivers high flexibility and adaptability to the welding process being able to adjust to complex joint geometries. Additionally, the application of a laser beam minimises the microstructural changes in the material due to the low heat application and low thermal distortion that the technology offers. Due to these advantages, laser welding technology is being adopted in technologically demanding markets such as EV battery manufacturing. However, these new application areas present challenges that must be overcome, such as joining dissimilar materials with different melting points and high reflectivity values in the typical laser wavelengths (Al, Cu). This work presents an adaptive control method for joining high reflectivity dissimilar materials using a dual laser beam setup to overcome these problems. As a result, a comparative study of different pulsed and continuous-wave laser arrangements through static and dynamic optics and the obtained joining qualities is presented.

关键词： Laser Beam Welding Fast Beam Manipulation Dissimilar Materials dynamic process control Edge Computing

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dynamic control for LMD processes using sensor fusion and edge computing

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Procedia CIRP 2022年 111卷 308-312页

作者： Beñat Arejita Iker Garmendia Juan Fernando Isaza Aitzol Zuloaga EXOM Engineering Avenida Altos Hornos de Vizcaya 33 Barakaldo 48901 Spain UPV/EHU Ingeniero Torres Quevedo Plaza 1 Bilbao 48013 Spain TEKNIKER C. Iñaki Goenaga 5 Eibar 20600 Spain

The quality of an LMD manufactured object highly depends on different process parameters such as the speed of powder deposition, the applied laser power, the powder feed rate, and other physical parameters such as the substrate temperature, resulting in a complex process. Consequently, applying corrections to the process parameters can be critical to improving the properties of the manufactured part. Some control approaches rely on open-loop techniques that use physical models and expert knowledge to adjust the tool path program in advance to compensate for deviations from the theoretical 3D model. Other approaches apply closed-loop control techniques to either control the melt pool during the process or adjust the tool path between layer depositions. This work presents a closed-loop control algorithm that dynamically controls three critical process parameters: the melt pool size, deposition speed, and standoff distance, combining data from a laser line profiler and a high-speed infrared camera.

关键词： Additive Manufacturing Laser Metal Deposition dynamic process control Edge Computing Industry 4.0

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