Topic
Process variable
About: Process variable is a research topic. Over the lifetime, 3983 publications have been published within this topic receiving 43130 citations. The topic is also known as: process parameter.
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TL;DR: In this paper, a high-resolution CCD video camera recorder was used to monitor the changing of the surface shape of molten alloy contacting the wheel tip under different conditions, and it was found that the mechanism of the wire formation during the optimum process condition was controlled by the momentum mechanism, while in the low wheel speed region, heat transfer turned out to be a dominant factor.
Abstract: Amorphous Co68.15Fe4.35Si12.25B15.25 wires with smooth surface and circular cross section were fabricated by melt extraction technology using a copper wheel with a knife-edge cross section angle of 60 deg. The effect of some process parameters such as wheel circumference velocity, molten alloy feed rate, and temperature on the geometry and weight, i.e., melt extracted layer thickness, of wire was examined carefully. An optimum process parameter to produce high-quality circular wires was presented. A high resolution CCD video camera recorder was used to monitor the changing of the surface shape of molten alloy contacting the wheel tip under different conditions. It was found that the mechanism of the wire formation during the optimum process condition was controlled by the momentum mechanism, while in the low wheel speed region, heat transfer turned out to be a dominant factor. Some characteristics of the circular wires such as amorphous nature and tensile strength were also studied.
52 citations
15 Jan 2005-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a physically based internal state variable microstructure model has been incorporated into the finite element simulation for an AA5083 aluminum alloy to predict the evolution of the material stored energy and the subsequent recrystallization after deformation is complete.
Abstract: Hot rolling, a critical process in the manufacturing of aluminum sheet products, can significantly impact the final properties of the cold rolled sheet. In this research, a mathematical model was developed to predict the through-thickness thermal and deformation history of a sheet undergoing single stand hot rolling using the commercial finite element (FE) package, ABAQUS ™ . A physically based internal state variable microstructure model has been incorporated into the FE simulation for an AA5083 aluminum alloy to predict the evolution of the material stored energy and the subsequent recrystallization after deformation is complete. The microstructure predictions were validated against experimental measurements conducted using the Corus pilot scale rolling facility in IJmuiden, the Netherlands for an AA5083 aluminum alloy. The model was able to predict the fraction recrystallized as well as the recrystallized grain size reasonably well under a range of industrially relevant hot deformation conditions. A sensitivity analysis was carried out to determine the influence of changing the material constants in the microstructure model and deformation conditions on the predicted recrystallization behaviour. The analysis showed that the entry temperature was the most sensitive process parameter causing significant changes in the predicted driving force for recrystallization, nucleation density, fraction recrystallized, and recrystallized grain size.
52 citations
TL;DR: In this paper, a grey relational grade analysis was used to optimize the spindle speed, feed rate, and drill diameter of hybrid glass fiber reinforced polymeric nanocomposites.
Abstract: Among many machining operations, drilling has become one of the important machining operations performed in polymer composites. The quality of the drilled hole is closely associated with the drilling parameters and conditions. The current work focuses on the optimization of multiple response characteristics during drilling of hybrid glass fiber reinforced polymeric nanocomposites. Taguchi’s L25, orthogonal array is used to conduct the experiments and for optimization of the process parameters. The machining parameters such as spindle speed, feed rate, and drill diameter are optimized for the response which includes delamination, thrust force and torque via grey relational analysis technique. From the grey relational grade analysis, it is clear that the drill diameter is the most influencing factor followed by the feed rate and the spindle speed. The optimized process parameter settings were found as spindle speed of 2700 rpm, the feed rate of 30 mm/min and drill diameter of 4 mm, respectively, for lower delamination, torque and thrust force. Among the various modeling techniques used, ANN is found to be suitable for the process with minimum error percentage of 0.526.
52 citations
TL;DR: In this paper, a pvT-based process control for the injection molding process is presented, where the quality determining process variable cavity pressure can be determined directly and a desired course of cavity pressure in the injection and holding pressure phases can be realized.
Abstract: The conventional control of the injection molding process is based on machine variables, which cannot sufficiently characterize the course of the process. Hence, a system that controls the injection molding process based on process variables has been developed at the Institute of Plastics Processing at RWTH Aachen University during the last years. It controls the quality determining process variable cavity pressure directly and realizes a desired course of cavity pressure in the injection and holding pressure phases. The cavity pressure course in the holding pressure phase is controlled online on the basis of pvT behavior of the processed plastic material. Thus, an optimal course of the process in the pvT diagram can be guaranteed and the quality constancy of the molded parts can be clearly increased. Using the pvT-based process control, the effect of varying mold and melt temperatures on the molded part weight can be decreased by about 90% compared with the conventional process control. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:65–76, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20153
52 citations
Patent•
22 Mar 1994TL;DR: In this paper, a method for determining whether a current state of a process variable output signal is within acceptable limits is presented, which is based on establishing reference data by sampling a plant's process variable signal when the plant is operating at steady state and analyzing the sampled output signal to derive normalized reference data including an energy content of each of a plurality of frequency components of the sampled signal.
Abstract: A method for determining whether a current state of a process variable output signal is within acceptable limits includes the following steps: establising reference data by sampling a plant's process variable output signal when the plant is operating at steady state and analyzing the sampled output signal to derive normalized reference data including an energy content of each of a plurality of frequency components of the sampled output signal. The procedure establishes a current operational data base by sampling a process variable signal when the plant is in operation. The sampled current output signal is analyzed to derive current data including a normalized energy content of each of a plurality of its frequency components. For each common frequency component of the reference data and the current data, the procedure compares their normalized energy contents and issues a non-steady state signal if the comparison indicates that the compared energy contents exceed a predetermined limit.
51 citations