Modern aircraft engines are nowadays designed with the aim of reducing fuel consumption and emission of pollutant gases as well as increasing reliability and competitiveness in the manufacturing and repair costs. Thes...
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Modern aircraft engines are nowadays designed with the aim of reducing fuel consumption and emission of pollutant gases as well as increasing reliability and competitiveness in the manufacturing and repair costs. These requirements on the engines result in new requirements on components and manufacturing processes, to know: application of new engineering materials, higher component temperatures, increased demands on tightness, 3-D complex shapes as well as new manufacturing technologies. EDM-machining is typically chosen for applications including complex geometries like high aspect ratio cavities in high-temperature resistant materials, since the EDM-process is independent from the mechanical properties of the processed material. This paper addresses the design and utilization of a unit composed of piezoelectric actuators for machining seal slots in turbine components. This aims the optimization of the flushing mechanisms through vertical vibration of the tool electrodes while manufacturing high aspect ratios cavities and therewith the optimization and/or reduction of both process time and electrode wear. Firstly, the piezo-unit was designed and components like piezoelectric actuators and charge amplifier were chosen, in accordance to previous defined requirements regarding vibration frequencies and amplitudes. During the experimental investigations graphite electrodes were applied. A total of twelve cavities with an aspect ratio of 12 are simultaneously machined in the material MAR-247. During the process, a harmonic longitudinal vibration of the electrodes overlapped to the machine's feed movement is realized. Both vibration amplitude and frequency were varied during the experiments, ranging from 2 μm to 16 μm and from 50 Hz to 1 kHz, respectively. The results are compared to the conventional process without vibration, while the EDM-parameters remain unaltered. By applying longitudinal vibration to the tool electrodes the material removal rate was increas
The principle of electrochemical machining (ECM) is based on the anodic dissolution of conductive work piece materials under the influence of an electric charge exchange. On the boundary surface between the metallic w...
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ISBN:
(纸本)9780956679000
The principle of electrochemical machining (ECM) is based on the anodic dissolution of conductive work piece materials under the influence of an electric charge exchange. On the boundary surface between the metallic work piece and a liquid ion conductor, called electrolyte, the work piece material is dissolved and carried out of the machining area by the electrolyte flow. As a special procedure electrochemical machining with closed electrolytic free jet (Jet-ECM) offers the machining of work pieces with extremely high current densities and a high localization of the machined area. Referring to this the Jet-EC Machining of carbide metal alloys is investigated in this study.
A typical characteristic of printing machines is their high level of exploitation. But modern offset presses are as well large and complex mechanical systems that use energy in a large variety of electrical drives, fo...
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ISBN:
(纸本)9783642290688
A typical characteristic of printing machines is their high level of exploitation. But modern offset presses are as well large and complex mechanical systems that use energy in a large variety of electrical drives, for heating, air conditioning and drying. Increasing energy prices make the reduction of energy consumption in the operation of printing presses a highpriority, market-relevant issue with an initial target of around 15 %. General and new engineering knowledge provides a variety of possible approaches for reducing energy consumption. The goal is to find an optimal compromise between additional, cost-creating measures for the machine builder and real cost-reducing benefits for the end user.
The engineering of artificial tissue and organs is widely gaining relevance in biotechnological and biomedical research. Particularly by the law enforced reduction of animal testing, alternative methods need to be dev...
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The engineering of artificial tissue and organs is widely gaining relevance in biotechnological and biomedical research. Particularly by the law enforced reduction of animal testing, alternative methods need to be developed to simulate and test the effects of chemical substances on human organs. Regarding the branches for pharmaceuticals, chemicals and cosmetics most products need to be tested on penetration of the human skin tissue. As an alternative method to animal testing, skin equivalents (SEs) based on tissue engineering may be used to test the skin barrier function. In the framework of a large scale research project, we built a fully automated production process based on the adaption of manual laboratory protocols to carry out the biological process steps for the manufacturing of SEs. In a first step, keratinocytes are mechanically and enzymatic isolated from human foreskin biopsies. In a second process, the cells are cultivated in MTP format cultivation dishes und undergo a series of passages. In a last process step, the keratinocytes are concentrated and dispensed in 24 well membrane based MTPs. Due to biological fluctuations in cell and tissue growth, the production process faces major challenges to control and process a vast variety in batch duration and timing. This results in a strong impact in the final tissue quality. For quality control in the manual process, histologies of the SEs are prepared followed by staining and microscopic imaging. To overcome this time intensive process, we developed a fully automated optical coherence tomography OCT system. OCT is a non- invasive and non-destructive imaging technique based on the interferometric detection of optical light feedback from the probe tissue in the near infrared light. OCT generates 2D and 3D tomographic images with a micron resolution and a tissue penetration up to 2 mm. We developed custom image processing algorithms, to detect the individual layer structure and corresponding layer thicknesse
In this paper the impact of different tool materials, tool coatings, and lubricants onto the micro forming process of micro cavities is investigated. As tool materials two different hardened steels were used for the f...
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ISBN:
(纸本)9780956679000
In this paper the impact of different tool materials, tool coatings, and lubricants onto the micro forming process of micro cavities is investigated. As tool materials two different hardened steels were used for the forming die. To lower the friction and adhesion between forming tool and aluminium substrate three coatings TiN (titanium nitride), TiCN (titanium carbon nitride), and DLC (diamond like carbon) were tested. Furthermore, the influences of different lubricants were studied. Geometric parameters and surface quality were judged by laser microscopy and SEM images of metallographic sections.
Data integration between different life cycle stages of a production system is a crucial requirement for the realization of continuous computer support what is often referred to as the Digital Factory. This paper pres...
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Data integration between different life cycle stages of a production system is a crucial requirement for the realization of continuous computer support what is often referred to as the Digital Factory. This paper presents an approach that leverages planning data within the operation phase of a production system by applying Semantic Web technologies and linked data concepts.
machine tool performance, production accuracy and energy efficiency are interdependent design criteria. To solve this design conflict, bionics – this means technical interpretation of long-term optimized biological p...
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machine tool performance, production accuracy and energy efficiency are interdependent design criteria. To solve this design conflict, bionics – this means technical interpretation of long-term optimized biological principles – could be an effective way to accelerate innovation loops in modern machine tool development processes. In the paper, these aspects will be discussed, and selected solutions will be presented in detail.
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