TY - RPRT A1 - Beisegel, Jesse A1 - Buhl, Johannes A1 - Izar, Rameez A1 - Schmidt, Johannes A1 - Bambach, Markus A1 - Fügenschuh, Armin ED - Fügenschuh, Armin T1 - Mixed-integer programming for additive manufacturing Y1 - 2021 U6 - https://doi.org/10.26127/BTUOpen-5731 CY - Cottbus ER - TY - GEN A1 - Omair, Muhammad A1 - Alkahtani, Mohammed A1 - Ayaz, Kashif A1 - Hussain, Ghulam A1 - Buhl, Johannes T1 - Supply Chain Modelling of the Automobile Multi-Stage Production Considering Circular Economy by Waste Management Using Recycling and Reworking Operations T2 - Sustainability N2 - The supply chain management plays a crucial role in delivering products from a supplier, through the manufacturer, distributors, and retailers to the targeted customers. The lifecycle of the products can be ended at any stage due to imperfect quality or waste, which are typically not managed well for a good price. This product’s life can be extended and increased with the use of the circular economy for the value addition processes which turn the waste into byproducts, which can be sold with maximum profit. The automobile industry is associated with various other small industries and is very significant for the economy at the local, national, and international levels. However, the industry also requires sustainable development in its supply chain management, gained by introducing the circular economy concept to manage and reduce the generated waste. The consumption of carbon fiber-reinforced composites (CFRCs) in the manufacturing of numerous automotive parts has acquired immense attention this decade, but the process also generates imperfect products (waste). The proposed model is based on a mathematical formulation to manage imperfect production by reworking and recycling, where the former is required to re-add value to the proportion of the rejected parts, and the latter is to recycle the remaining scrap into useful products by using a circular economy. The outsourcing operation is also added to provide an optimal level of inventory and lot sizing for minimizing the total cost of the supply chain management. Data from the automobile part industry are tested to provide the practical implications of the proposed SCM mathematical model. Sensitivity analysis is performed to understand the significance level of the individual parameters affecting the objective function, i.e., the total cost of the SCM. The results show a meaningful insight for the managers to obtain the benefits of the circular economy in multi-stage automobile part production for sustainable and resilient supply chain management. KW - supply chain management KW - circular economy KW - automotive industry KW - outsourcing KW - imperfect production Y1 - 2022 U6 - https://doi.org/10.3390/su142215428 SN - 2071-1050 VL - 14 IS - 22 ER - TY - GEN A1 - Hussain, Ghulam A1 - Alkahtani, Mohammed A1 - Alsultan, Marwan A1 - Buhl, Johannes A1 - Gupta, Munish Kumar T1 - Chip formation, cutting temperature and forces measurements in hard turning of Gcr15 under the influence of PcBN chamfering parameters T2 - Measurement KW - Chamfering width KW - Chamfering angle KW - DEFORM KW - Hard turning Y1 - 2022 U6 - https://doi.org/10.1016/j.measurement.2022.112130 SN - 1873-412X SN - 0263-2241 VL - Vol. 204 ER - TY - GEN A1 - Gerold, Stefanie A1 - Buhl, Johannes A1 - Geiger, Sonja M. T1 - How to Enhance Time Wealth? Insights from Changes in Time Use and Working Conditions During the COVID-19 Lockdown in Germany T2 - Social Indicators Research N2 - This paper investigates the changes in time use, working conditions and subjective time wealth during the COVID-19 pandemic in Germany. Our analysis draws on panel data collected before and during the first lockdown among 786 employees. It employs a recently developed scale on time wealth which has been suggested as a comprehensive measure to capture the subjective experience of time. We provide separate analyses according to gender and essential occupation. First-difference regressions are applied to examine how changes in time use and changes in working conditions during the lockdown affected subjective time wealth. Our results show a general growth in time wealth during the lockdown which is, among other factors, driven by a decline in work hours and an increase in sleep duration. We also find positive effects on time wealth from decreased time pressure at work, more autonomy in organising one’s working day, and an improved reconciliation of work and private life. This study contributes to existing research by identifying key aspects how to improve time wealth among employees. Y1 - 2023 U6 - https://doi.org/10.1007/s11205-023-03252-0 SN - 1573-0921 VL - 171 SP - 349 EP - 371 ER - TY - GEN A1 - Grüger, Lennart A1 - Fischer, Tim Sebastian A1 - Woll, Ralf A1 - Buhl, Johannes T1 - Absicherung von Risiken beim Prozess des Wire Arc Additive Manufacturing T2 - Industry 4.0 Science KW - Additive Manufacturing KW - Wire Arc Additive Manufacturing KW - Failure Mode and Effects Analysis Y1 - 2024 U6 - https://doi.org/10.30844/I4SD.24.1.63 SN - 2942-6154 VL - 2024 IS - 1 SP - 63 EP - 69 ER - TY - GEN A1 - Grüger, Lennart A1 - Fischer, Tim Sebastian A1 - Woll, Ralf A1 - Buhl, Johannes T1 - Safeguarding Against Risks in the Wire Arc Additive Manufacturing Process T2 - Industry 4.0 Science N2 - In this article, the potential risks in wire arc additive manufacturing are analyzed using failure mode and effects analysis. To achieve this, 186 possible causes of risk were analyzed and the five most critical risks were discussed in detail. Four significant risk factors were identified in the construction process. The fifth risk relates to the shielding gas flow. This is only one influencing factor among the welding parameters, which have strong interactions with each other. Therefore, their relationships should be analyzed on the basis of numerous tests. KW - additive manufacturing KW - wire arc additive manufacturing KW - failure mode and effects analysis Y1 - 2024 U6 - https://doi.org/10.30844/I4SE.24.1.63 SN - 2942-6170 VL - 2024 IS - 1 SP - 63 EP - 69 ER - TY - RPRT A1 - Grüger, Lennart A1 - Sydow, Benjamin A1 - Woll, Ralf A1 - Buhl, Johannes T1 - Design of a Cost-Effective and Statistically Validated Test Specification with Selected Machine Elements to Evaluate the Influence of the Manufacturing Process with a Focus on Additive Manufacturing N2 - Due to their versatile advantages, the use of additively manufactured components is growing. In addition, new additive manufacturing processes are constantly being developed, so that a wide range of printing processes are now available for metal. Despite the same starting material, the microstructure and thus also the final mechanical properties differ greatly compared to conventional processes. In most cases, only direction-dependent characteristic values from the uniaxial tension are used to qualify a printing process before it is used. The literature, on the other hand, demonstrates that the results are not transferable to other loading conditions. In this work, several engineering tests were integrated into a single test specimen so that they can be determined on the same specimen. The test specimen can be used to test tooth root strength, bending strength, notched bar impact energy, and thread strength depending on the mounting direction, thus representing industrial loading cases. In this study, test specimens were fabricated by conventional manufacturing (machining), L-PBF (Laser Powder Bed Fusion), and WA-DED (Wire Arc Direct Energy Deposition), and the results were compared using statistical methods. Factors to capture manufacturing influence and buildup direction were statistically validated on 316L. The work shows a benchmark with a typical initial microstructure of rolled and milled material, L-PBF, and WA-DED parts on loads close to the application and thus simplifies an industry-oriented evaluation of a new manufacturing process. KW - manufacturing factor KW - testing specification KW - laser powder bed fusion KW - wire arc direct energy deposition KW - 316L KW - significance KW - statistical method KW - benchmark geometry Y1 - 2023 UR - https://www.mdpi.com/2075-4701/13/11/1900 U6 - https://doi.org/https://doi.org/10.3390/met13111900 ER -