An evaluation of building sets designed for modular machine tool structures to support sustainable manufacturing

The modularization of machine tool frames is an approach when designing new machine tool structures in a sustainable context. By integration of microsystem technology and designing lightweight modules, a smart alternative to conventional machine tool frames is developed. In previous studies, this concept has been evaluated along with a compilation of the possible use-case scenarios and the potential benefits from using modular electronics. In the presented paper, the geometric requirements from the selected use-case scenarios for machine tool structures are identified by dividing the structures in their ideal mechanic equivalents. A set of rules is developed driven by the generalized geometric requirements of the machine tool frames. Three different approaches of polyhedral building sets are shown and evaluated for their merits based on criteria of geometric functionality and sustainability. Finally, a prototypical modular portal frame is presented for the proof of concept

Addressing sustainability and flexibility in manufacturing via smart modular machine tool frames to support sustainable value creation

Sustainability and flexibility are crucial aspects in todays’ manufacturing processes. Within this study an innovative approach of modular machine tool frames (MMTF) equipped with micro system technology is presented that aims at enhancing flexibility of mutable production processes. This new approach extends the existing reconfigurable manufacturing systems (RMS). MMTF goes beyond the platform approach via minimizing the machine tool frame parts used for the building block system of manufacturing cells. The concept has been realized by integration of modularized microelectronics and actuators enabling for integrity and accuracy of the machine tool frame. In this contribution, sustainable hotspots for the production of the MMTF are identified via a tiered life cycle sustainability assessment. From these findings, new approaches are derived that provide for a reasonable usage of mechanical and electronic components in MMTF for sustainable value creation

In-situ prediction of the spatial surface roughness profile during slot milling

Quality inspection is traditionally considered non-productive. That is why the manufacturing industries aim to decrease inspection times to a bare minimum without sacrificing part quality. Alongside the implementation of the Industry 4.0 paradigm, data-driven in-situ quality control is a potential enabler for minimizing inspection times. In that, the surface roughness parameter prediction is the subject of a large body of research, but studies on the spatial surface roughness profile prediction are limited. This research contributes to this field by using vibration signals and physics-informed machine learning models for the in-situ prediction of the surface roughness profile. A tri-axial accelerometer mounted on the machine tool spindle is used to capture the vibrations during a slot milling process. For one tool revolution during a stable cut, the observed acceleration in the three axes and the surface roughness profile are periodic. A model is constructed to establish the correlation between the input signals and the spatial surface roughness profile by utilizing a physics-based model of the tool trajectory together with a two-layer feed-forward neural network. Furthermore, the feature engineering of denoised velocities and displacements derived by the numerical integration of the acceleration signals improves the prediction performance with overfitting. The results show a good correlation between the spatial surface roughness and the accelerometer signals

Assessment of Fault Detection and Monitoring Techniques for Effective Digitalization

As a result of digitalization, data is collected at every level of production as an enhancer for decision-making. However, including more sensors to collect additional information does not directly contribute to increasing the system reliability but instead raises challenges for optimal data utilization. This work presents an evaluation approach based on FMSA (Failure mode and symptoms analysis) combined with FMECA (Failure mode, effects and criticality analysis) prioritization methods. The different methods are applied to a feed-drive system to evaluate the suitability of the currently implemented detection and monitoring techniques. The recommendations derived from the evaluation can be utilized to maximize confidence in the monitoring and to minimize the sensors utilization and data collection. Since the FMEA family of assessment tools present shortcomings such as bias and uncertainty associated with their results, this work also aims at mitigating these effects in obtaining the monitoring priority numbers and their respective categorization and prioritization.Part of ISBN 978-981-18-8071-1QC 20231220RoD

Phase Transition Behavior and Oriented Aggregation During Precipitation of In(OH)₃ and InOOH Nanocrystals

The phase transition behavior and oriented aggregation (OA) during colloidal synthesis of In­(OH)₃ nanocrystals in water are investigated by TEM, SEM, X-ray diffraction, and density functional theory (DFT) calculations. Besides the cubic In­(OH)₃ phase, also orthorhombic InOOH is formed in a precipitation route using indium acetate as the In³⁺ source. Well-developed nano- and microcuboids are observed that consist solely of In­(OH)₃. In contrast, the InOOH phase remains semicrystalline even for long reaction (refluxing) times. The irregular growth of the InOOH phase is explained by proton transfers from hydroxyl groups to oxygen ions within the InOOH lattice that lead to OH disorder and lattice strain. DFT calculations of the surface energies of ideal and water-saturated low-index InOOH and In­(OH)₃ surfaces predict that the In­(OH)₃ phase becomes energetically more favorable than InOOH above a critical crystallite size. This explains why InOOH is formed before the In­(OH)₃ phase, which is an unusual pathway for a hydrothermal process. Once InOOH has transformed to In­(OH)₃ by incorporation of water, the crystallites can grow without restriction due to the disappearance of OH-disorder-induced strain. Finally, for the In­(OH)₃ cuboids a three-step formation process is suggested: In the first step, one-dimensional OA under formation of nanorods occurs. In the second step, parallel bundles are formed from the nanorods. In the third step these bundles merge into cuboids by three-dimensional OA

Transformative Wirtschaftswissenschaft im Kontext nachhaltiger Entwicklung : für einen neuen Vertrag zwischen Wirtschaftswissenschaft und Gesellschaft

In einem gemeinsamen Artikel regen die Autorinnen und Autoren die Diskussion eines neuen Vertrages zwischen Wirtschaftswissenschaft und Gesellschaft an. Sie diskutieren die Chancen, Möglichkeiten und die Verantwortung transformativer Wirtschaftswissenschaft (in besonderem Hinblick auf Nachhaltigkeit) und betten diese in den wissenschaftlichen Diskurs ein. Transparenz, Reflexivität, Werbebezug, Partizipation und Umgestaltung von Forschung und Lehre - das sind nach Ansicht der Autor(inn)en die fünf Bedingungen, welche eine transformative Wirtschaftswissenschaft genügen muss. Der Artikel dient als Denk- und Diskussionsanstoß innerhalb der Wirtschaftswissenschaften sowie auch zwischen Wirtschaftswissenschaft und jenen außenwissenschaftlichen Akteuren, die in gesellschaftlicher und ökonomischer Transformation in Richtung Nachhaltigkeit engagiert sind. Die Spiekerrooger Klimagespräche 2016 werden darauf aufbauen