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INHALT: l. Einleitung und Standortbestimmung 2. Japanische Wertvorstellungen 3. Inhalte der Lean Production 4. Fertigungssegmentierung 5. Informationsmanagement mit CIM- und Logistik-Komponenten 6. Logistikgerechte Strukturen der Lean Production 7. Realisierung der Lean Production 8. Zusammenfassung
Against the background of climate change and finite fossil resources, bio-based plastics have been in the focus of research for the last decade and were identified as a promising alternative to fossil-based plastics. Now, with an evolving bio-based plastic market and application range, the environmental advantages of bio-based plastic have come to the fore and identified as crucial by different stakeholders. While the majority of assessments for bio-based plastics are carried out based on attributional life cycle assessment, there have been only few consequential studies done in this area. Also, the application of eco-design strategies has not been in the focus for the bio-based products due to the prevailing misconceptions of renewable materials (as feedstock for bio-based plastics) considered in itself as an ‘eco-design strategy’. In this paper, we discuss the life cycle assessment as well as eco-design strategies of a bio-based product taking attributional as well as consequential approaches into account.
This paper presents a cascaded methodology for enhancing the path accuracy of industrial robots by using advanced control schemes. It includes kinematic calibration as well as dynamic modeling and identification. This is followed by a centralized model-based compensation of robot dynamics. The implemented feed-forward torque control shows the expected improvements of control accuracy. However, external measurements show the influence of joint elasticities as systematic path errors. To further increase the accuracy an iterative learning controller (ILC) based on external camera measurements is designed. The implementation yields to significant improvements of path accuracy. By means of a kind of automated ”Teach-In”, an overall effective concept for the automated calibration and optimization of the accuracy of industrial robots in high-dynamic path-applications is realized.
l. Einleitung/Ausgangssituation - Auswirkungen unabgestimmter Prozesse - Prozeßnahe Werkstattsteuerungen 2. Defizite, Prozeßanforderungen - Daten-Anforderungsprofil - Datenvolumen-Trichtermodell - Argumente für Leitstand-Einsatz 3. Integrierter Leitstandeinsatz - Top-Down-Ansatz - Integrierte Regelkreise - Hierarchisches Planungs- und Steuerungskonzept 4. Abgrenzung zwischen Leitstand-, PPS und BDE-Funktionen - Ressourcen-Verfügbarkeitsanforderungen - Leitstand-Funktionsumfang - Integrierter Logistik-Sollablauf 5. Kennzeichen der 2ten Leitstandgeneration - Wissensbasierter LS-Einsatz - Event-Steuerungen 6. Anforderungsgerechte Leitstandeinführung - CIM-house-Modell - Mitarbeiter-Anforderungen
In vielen Fällen muss vor dem Kleben eine Klebflächenbehandlung durchgeführt werden, da Klebverbindungen mit unvorbehandelten Teilen häufig zu geringe Klebfestigkeiten und/oder eine unzureichende Alterungsbeständigkeit aufweisen. Zur Klebflächenbehandlung stehen unterschiedliche Verfahren zur Verfügung. Wenn mit mehreren Behandlungen klebtechnisch einwandfreie Verbindungen hergestellt werden können, gilt es, das Verfahren zu ermitteln, welches am besten in den Fertigungsfluss integriert werden kann und die geringsten Kosten verursacht. Dabei muss auch die Arbeitssicherheit und der Umweltschutz mit beachtet werden. Zur Beurteilung der Verfahren werden Bewertungskriterien gegeben. Die Verfahren werden abschließend kurz charakterisiert.
The technical, environmental and economic potential of hemp fines as a natural filler in bioplastics to produce biocomposites is the subject of this study – giving a holistic overview. Hemp fines are an agricultural by-product of the hemp fibres and shives production. Shives and fibres are for example used in the paper, animal bedding or composite area. About 15 to 20 wt.-% per kg hemp straw results in hemp fines after processing. In 2010 about 11,439 metric tons of hemp fines were produced in Europe. Hemp fines are an inhomogeneous material which includes hemp dust, shives and fibre. For these examinations the hemp fines are sieved in a further step with a tumbler sieving machine to obtain more specified fractions. The untreated hemp fines (ex work) as well as the sieved fractions are combined with a polylactide polymer (PLA) using a co-rotating twin screw extruder to produce biocomposites with different hemp fine content. By using an injection moulding machine standard test bars are produced to conduct several material tests. The Young’s modulus is increased and the impact strength reduced by hemp fines. With a content of above 15 wt.-% hemp fines are also improving the environmental (global warming potential) and economic performance in comparison to pure PLA.
Techno-economic analysis that allocate costs to the energy flows of energy systems are helpful to understand the formation of costs within processes and to increase the cost efficiency. For the economic evaluation, the usefulness or quality of the energy is of great importance. In exergy-based methods, this is considered by allocating costs to the exergy instead of energy. As exergy represents the ability of performing work, it is often named the useful part of energy. In contrast, the anergy, the part of energy, which cannot perform work, is often assumed to be not useful.
However, heat flows as used e.g. in domestic heating are always a mixture of a relative small portion of exergy and a big portion of anergy. Although of lower quality, the anergy is obviously useful for these applications. The question is, whether it makes sense to differentiate between exergy and anergy and take both properties into account for the economic evaluation.
To answer this question, a new methodical concept based on the definition of an anergy-exergy cost ratio is compared to the commonly applied approaches of considering either energy or exergy as the basis for economic evaluation. These three different approaches for the economic analysis of thermal energy systems are applied to an exemplary heating system with thermal storages. It is shown that the results of the techno-economic analysis can be improved by giving anergy an economic value and that the proposed anergy-cost ratio allows a flexible adaptation of the evaluation depending on the economic constraints of a system.
Flatness-based feedforward control is an approach for combining fast motion with low oscillations for nonlinear or flexible drive systems. Its desired trajectories must be continuously differentiable to the degree of the system order. Designing such trajectories, that also reach the dynamic system limits, poses a challenge. Common solutions, like Gevrey functions, usually require lengthy offline calculations. To achieve a quicker and simpler industrial-suited solution, this paper presents a new online trajectory generation scheme. The algorithm utilizes higher order s-curve trajectories created by a cyclic filtering process using moving average filters. An experimental validation proves the capability as well as industrial applicability of the presented approach for flexible structures like stacker cranes.
We present a feedback-corrected optimal scheduling approach to reduce the demand of electrical energy of batch processes, exemplified at the sand preparation in foundry. The main energy driver in the exemplary foundry is the idle time of the batch-wise working sand mixers. In this novel approach, we use linear integer programming to minimize the demand of energy of the sand mixers by scheduling the batches in real-time. For the optimization we use a physical model of the sand preparation, which takes dwell-times of the processes as dead-time systems into account. In this paper, we present the steps to make the optimal scheduling approach applicable for the production process. The application at the real production plant proves the performance of the suggested approach. Compared to the conventional control, the feedback-corrected optimal scheduling approach leads to an reduction in energy consumption of approximately 6.5 % without modifying the process or the aggregates.