Fraunhofer Institute for Manufacturing Engineering and Automation

Spray painting is still a poorly manageable process due to the complex interaction of physical, chemical and environmental influences like turbulent air flows, strong electrostatic fields, complex viscosity of paints and paint booth conditions. Consequently, many important properties of the painted film, like thickness, color, surface structure and the efficiency of the process are not controllable in an adequate manner, despite the enormous economic ramifications of poor quality control in high volume applications, such as in the automotive industry. This study shows how novel, online spray monitoring can instantaneously generate characterizing quantities from the spray to detect harmful deviations in the process. In this study, several minute changes have been experimentally imposed on a paint system, such as changed paint viscosity or pigmentation, deviations in air flow and paint flow rates, and defective or used and worn equipment parts. It will be shown that all these deviations lead to features which allow a clear distinction from the intact and reference cases. Additionally, it is shown that most of the deviations, if not detected, would have led to quality issues of the paint coating.

Loose and baggy clothing is required by the rules of ski cross and snowboard cross. However, it is known from the literature that fluttering garments increase the aerodynamic drag. The aim of this study was to investigate the influence of flexural rigidity and fabric weight on the coefficient of drag C D . Eleven fabrics (550 mm long, 320 mm wide) with different flexural rigidity (0.016–99 µNm) and fabric weight (0.1–2.4 N/m ² ) were tested in a wind tunnel on a cylinder (width 325 mm, diameter 125 mm) at speeds of 25 to 120 kph (Reynolds numbers Re 60 k-280 k). The general trend showed that fluttering fabrics that are heavier and stiffer create more drag force. All but one fabric had a smaller C D than the bare cylinder in the subcritical flow regime ( C D ≈ 1.1), at least within a Re window of 80 k. One fabric had a consistently higher C D (average: 1.27) than the bare cylinder. The mean C D value of the other ten fabrics ranged from 0.87 to 1.07, with minimum C D values between 0.76 and 1. The C D advantage of the ten fabrics ended at the beginning of the critical flow regime of the bare cylinder between Re 200 k and 220 k. A regression analysis showed that the magnitude of the C D is more influenced by the flexural rigidity of a fabric, normalised to its weight, than by the weight itself, at least at Re < 250 k. The results of this study suggest that ski and snowboard cross athletes’ suits should be made from light and flexible fabrics to reduce aerodynamic drag.

Cette étude centrée sur le suivi de l’insuffisance respiratoire (IR) des patients atteints de maladies neuromusculaires (MNM) met l’accent sur la nécessité d’améliorer l’offre de soins et de pallier les ruptures de parcours. L’infirmier(ère) en pratique avancée (IPA), dans une dynamique pluridisciplinaire, pourrait ainsi être le maillon manquant. L’amélioration de la prise en charge des MNM est au cœur des préoccupations de la filière de santé maladies rares neuromusculaires Filnemus, des centres de référence et de l’AFM-Téléthon. C’est aussi, chez eux, que se discutent les besoins d’IPA spécialisée dans les affections neuromusculaires et qui pourrait répondre à des besoins non couverts ou insuffisamment couverts dans le parcours de santé.

The electrolyte filling and subsequent wetting of the active material is a time‐critical process in the manufacturing of lithium‐ion batteries. Due to the metallic cell housing, the process phenomena are insufficiently accessible, preventing the replication of the wetting processes by mathematical or simulative methods and hindering efforts to accelerate the wetting process. Therefore, this publication employs a glass cell housing for electrolyte filling of a 21700 cylindrical cell to investigate the wetting at different temperatures and process pressures. In parallel, a mathematical replication of the wetting, as well as a lattice Boltzmann pore‐scale simulation, is used to evaluate the influence of these varying process boundary conditions. The results show a strong temperature dependence on electrolyte wetting and the positive effect of pressure changes in the wetting process. These findings are particularly relevant to the process design of large‐scale cylindrical cell manufacturing.

Business processes often deviate from their expected or desired behavior. Such deviations can be either positive or negative, depending on whether or not they lead to better process performance. Deviance mining addresses the problem of identifying such deviations and explaining why a process deviates. In this paper, we propose a novel approach to identify and explain the causes of deviant process executions based on the technique of redescription mining, which extracts knowledge in the form of logical rules. By analyzing, comparing, and filtering these rules, the reasons for the deviant behaviors of a business process are identified both in general and for particular process instances. Afterward, the results of this analysis are transformed into a concise and well-readable natural language text that can be used by business analysts and process owners to optimize processes in a reasoned manner. We evaluate our approach from different angles using four process models and provide some advice for further optimization.

The aerospace sector is looking for lighter, more robust, and less fuel-consuming aircraft by using advanced lightweight materials. Fibre-reinforced polymers and lightweight alloys are pivotal to this aim, owing to their favourable strength-to-weight ratio and mechanical properties. Therefore, assembling hybrid stacks of these materials offers customisation opportunities to optimise performance and structural integrity. This research explores one-up drilling techniques for hybrid stacks of carbon fibre-reinforced polymer (CFRP) laminates and aluminium alloy sheets, which are essential in the fabrication of advanced aircraft structures. The experimental procedure consists of first drilling individual materials separately to optimise the process parameters for each material and then drilling a hybrid stack configuration (CFRP/AA7075-T6) with an innovative approach using spindle active power monitoring to implement a self-adapting strategy of process parameters at the interface between the two materials. This flexible methodology offers a practical solution for streamlining the drilling process in aerospace applications.

The increase in global demand for lithium-ion battery cells has driven the establishment of numerous manufacturing facilities. However, the complex design and manufacturing of Li-ion battery cells pose several challenges, such as ensuring high cell quality while maintaining high process stability and efficiency. During the usage phase, factors such as operating conditions, and charging/discharging profiles can significantly impact the performance and longevity of battery cells. Furthermore, addressing recycling and proper disposal in the end-of-life phase presents substantial challenges, given the risks associated with hazardous materials and the scarcity of resources. Hence, effective management of these phases is essential for achieving sustainable and efficient energy storage systems. Digital twins applied in various industries have shown promising results in improving product lifecycle management and smart manufacturing processes. However, it is important to scientifically test and validate its effectiveness within the specific context of the battery industry. The main question is whether digital twins can realistically address the growing challenges of the battery industry, such as degradation evaluation, usage optimization, manufacturing inconsistencies, second-life application possibilities, etc. Without a thorough understanding of the benefits of digital twins, it is difficult to claim that they are the best solution for the battery industry's challenges. This chapter explores the potential applications and use cases of digital twins in the battery lifecycle, outlining the requirements and concepts necessary for implementing digital twins effectively. This approach ensures a comprehensive understanding of the system's benefits and limitations, thereby enabling stakeholders to make informed implementation decisions.

This review reports on the use of sensors in wheelchair sports to monitor and analyze performance during match and training time. With rapid advancements in electronics and related technologies, understanding performance metrics in wheelchair sports is essential. We reviewed nine studies using various sensor types, including electric motors, inertial measurement units, miniaturized data loggers with magnetic reed switches, and smartphones with inbuilt accelerometers and gyroscopes, operating at frequencies from 8 Hz to 1200 Hz. These studies measured parameters such as angular and translational velocities, distance, number of starts/pushes, and other performance indicators in sports such as basketball, rugby, tennis, and racing. Despite differences in sport types and methodologies, most studies found sensor-derived data effective for assessment of performance. Future developments and research in this field should focus on multi-sensor systems that could provide real-time match analysis and deeper insights into performance metrics. Overall, sensor technologies show significant potential for improving wheelchair sport performance diagnostics, contributing to better athlete training and future wheelchair design, and enhancing competitive outcomes. This review emphasizes the need for continued innovation and standardization in applying sensor technologies in wheelchair sports.

Drag is a key criterion in assessing the quality of thermally cut sheet metal edges, which is critical to the reliability of the final product. The evaluation of drag has been described qualitatively and quantitatively, but the scientific literature lacks a methodical description of algorithmic tracking of the drag lines themselves. This absence of a standardized approach has hindered the objective determination of drag. With recent advances in the field towards automated quality assessment aimed at autonomous adaptation of process parameters, the need for consistent, fast and reliable assessment of drag lines has become apparent. To address this gap, this study introduces an innovative drag line tracking algorithm, inspired by the behavior of fluid flowing towards the lowest points, to compute a generalized drag line for an edge with a homogeneous cutting pattern. The algorithm utilizes the height data of the measured cut edges as a data base for the assessment of the drag lines. The results indicate that the drag lines identified by the algorithm are not only subjectively accurate, but also show a strong correlation with human-annotated drag lines across several metrics. This work lays the foundation for the objective evaluation of drag by not only describing an algorithm for the consistent determination of drag lines, but also by presenting a tool for human annotation and suitable customized metrics. As a result, it contributes significantly to the comprehensive evaluation of edge quality and represents a step forward in the automatic optimization of process parameters and the improvement of cutting edge quality.

The division of the polymer laser powder bed fusion process polymers (PBF‐LB/P) into temporal regimes originating from laser motion, thermal diffusion, viscous flow, crystallization kinetics, and powder application is exploited by considering only the building direction. The reduction of dimensionality enables fast simulations which are used to investigate the influence of the inter layer time on the final part density. Numerical simulation results are validated by experiments using polyamide 12 (PA 12) with good agreement in terms of part density. It is shown that an inter layer time of 90 s leads to nearly dense PA 12 parts while a time of 45 s leads to less dense parts. The cooling effect of the applied powder is identified as a cause for insufficient densification of the previous layer. The simulation tool is quantitatively validated against experimental results for the surface temperature of PA 12 as function of scan speed and hatch distance, for the melt pool depth of polyamide 6 as function of scan speed and for the melt pool depth of polyetherketoneketone as function of laser power. The presented simulation method enables rapid process parameter adjustment for new polymer materials in the PBF‐LB/P process.

Knowledge of contact forces between instruments and blood vessels during endovascular interventions like thrombectomies can help make these interventions safer and faster. We show that it is generally feasible to derive the contact forces directly from the intraoperative fluoroscopy imaging system which can make the costly integration of additional sensors into catheters and guidewires dispensable. Our study is limited to stationary normal loading and planar deflections. In our loading scenario of crossing the carotid siphon with a guidewire, the magnitude of contact forces can be detected up to an average deviation of 4.5 % for an imagebased pose measurement accuracy of the guidewire of 1 mm.

Purpose Solid-state batteries (SSBs) are a current research hotspot, as they are safer and have a higher energy density than state-of-the-art lithium-ion batteries (LIBs). To date, their production only occurs on a laboratory scale, which provides a good opportunity to analyze the associated environmental impacts prior to industrialization. This paper investigates the environmental impacts of the production of cylindrical SSB, to identify environmental hotspots and optimization potentials. Methods Here, an attributional cradle-to-gate life cycle assessment (LCA) is performed, focusing on SSBs that use a NMC811/lithium germanium phosphorous sulfide (LiGPS) composite cathode, a sulfide-based solid separator electrolyte, and a lithium metal anode. The life cycle impact assessment (LCIA) is performed in Umberto 11 using the Environmental Footprint 3.1 method with primary and literature data and the Evoinvent 3.9 database for background data. Results and discussion The results show climate change impacts of 205.43 kg CO2 eq./kwh (for the base case), with hotspots primarily attributable to the electrolyte and cathode production, and more specifically to the LiPS and LiGPS synthesis as well as to the cathode active material. Additionally, the scenario analysis shows that an upscaling of the LiPS and LiGPS synthesis reduces environmental impacts across all assessed impact categories. In addition, it was shown that the use of an in situ anode further improves the overall environmental performance, while the use of alternative cathode active materials, such as NMC622 and LFP did not lead to any improvements, at least with reference to the storage capacity. Conclusion The article highlights the environmental hotspots of sulfide-based SSB production, namely electrolyte and catholyte synthesis. The results show that upscaling the synthesis reduces the environmental impact and that cells with higher energy density show a favorable environmental performance. However, SSBs are still in the development stage and no final recommendation can be made at this time.