360 research outputs found
Planning Machine Activity Between Manufacturing Operations: Maintaining Accuracy While Reducing Energy Consumption
There has recently been an increased emphasis on reducing energy consumption in manufacturing. This is largely because of fluctuations in energy costs causing uncertainty. The increased competition between manufacturers means that even a slight change in energy consumption can have implications on their profit margin or competitiveness of quote. Furthermore, there is a drive from policy-makers to audit the environmental impact of manufactured goods from cradle-to-grave. The understanding, and potential reduction of machine tool energy consumption has therefore received significant interest as they require large amounts of energy to perform either subtractive or additive manufacturing tasks.
One area that has received relatively little interest, yet could harness great potential, is reducing energy consumption by optimally planning machine activities while the machine is not in operation. The intuitive option is to turn off all non-essential energy-consuming processes. However, manufacturing processes such as milling often release large amounts of heat into the machine's structure causing deformation, which results in deviation of the machine tool's actual cutting position from that which was commanded, a phenomenon known as thermal deformation. A rapid change in temperature can increase the deformation, which can deteriorate the machine's manufacturing capability, potentially producing scrap parts with the associated commercial and environmental repercussions. It is therefore necessary to consider the relationship between energy consumption, thermal deformation, machining accuracy and time, when planning the machine's activity when idle, or about to resume machining.
In this paper, we investigate the exploitability of automated planning techniques for planning machine activities between subtractive manufacturing operations, while being sufficiently broad to be extended to additive processes. The aim is to reduce energy consumption but maintain machine accuracy. Specifically, a novel domain model is presented where the machine's energy consumption, thermal stability, and their relationship to the overall machine's accuracy is encoded. Experimental analysis then demonstrates the effectiveness of the proposed approach using a case study which considers real-world dat
Production of Poly(vinylalcohol) Nanoyarns Using a Special Saw-like Collector
This work introduces an electrospinning method for laboratory-scale production of nanofibrous materials from polyvinylalcohol (PVA) nanofibres. A procedure for the subsequent production of twisted yarns from the aligned nanofibrous strand is introduced as well. Both needle and needleless electrospinning variants were employed Mechanical properties of the nanoyarns produced were tested using a VIBRODYN 400 and their morphology was investigated by light and electron microscopy. The work also introduces a simple analysis of the field strength that causes the prevailing unidirectional fiber deposition between neighbouring lamellae of a special saw-like collector The field strength analysis was carried out both analytically and by modelling based on the software COMSOL Multiphysics.MSMT project CARSILA [ME10145]; [GACR: P208/12/0105
Regeneration of Murine Erythropoiesis in Individual Bone Marrow Regions (Bones) and Spleen in Lethally Irradiated Marrow Graft Recipients
The proposal of the closure element pipe
The present paper summarizes the basic equations describing the behavior of butterfly valves during the fluid flow. Butterfly valves are used as a safety element in the energy industry, petrochemical industry, in steam lines etc. The paper describes the theoretical determination of the control torque on the closure element, the torque causes the opening and closing of butterfly valve. Determination of this torque depends on many factors, geometry of the closure element, misalignment to the axis of fluid flow, control method of valve, method of imposition of the moving member and of course on the operating parameters. Correct determination of the torque affects the proper design butterfly valves and ensure its functionality, which can prevent damage to other elements of the monitoring system
BEER - The Beamline for European Materials Engineering Research at the ESS
The Beamline for European Materials Engineering Research (BEER) will be built at the European Spallation Source (ESS). The diffractometer utilizes the high brilliance of the long-pulse neutron source and offers high instrument flexibility. It includes a novel chopper technique that extracts several short pulses out of the long pulse, leading to substantial intensity gain of up to an order of magnitude compared to pulse shaping methods for materials with high crystal symmetry. This intensity gain is achieved without compromising resolution. Materials of lower crystal symmetry or multi-phase materials will be investigated by additional pulse shaping methods. The different chopper set-ups and advanced beam extracting techniques offer an extremely broad intensity/resolution range. Furthermore, BEER offers an option of simultaneous SANS or imaging measurements without compromising diffraction investigations. This flexibility opens up new possibilities for in-situ experiments studying materials processing and performance under operation conditions. To fulfil this task, advanced sample environments, dedicated to thermo-mechanical processing, are foreseen
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