Browsing by Author "Clare, Adam T."

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    Manufacturing at double the speed
    (Elsevier, 2015-11-02) Allwood, Julian M.; Childs, Tom H. C.; Clare, Adam T.; De Silva, Anjali K. M.; Dhokia, Vimal; Hutchings, Ian M.; Leach, Richard K.; Leal-Ayala, David R.; Lowth, Stewart; Majewski, Candice E.; Marzano, Adelaide; Mehnen, Jorn; Nassehi, Aydin; Ozturk, Erdem; Raffles, Mark H.; Roy, Rajkumar; Shyha, Islam; Turner, Sam
    The speed of manufacturing processes today depends on a trade-off between the physical processes of production, the wider system that allows these processes to operate and the co-ordination of a supply chain in the pursuit of meeting customer needs. Could the speed of this activity be doubled? This paper explores this hypothetical question, starting with examination of a diverse set of case studies spanning the activities of manufacturing. This reveals that the constraints on increasing manufacturing speed have some common themes, and several of these are examined in more detail, to identify absolute limits to performance. The physical processes of production are constrained by factors such as machine stiffness, actuator acceleration, heat transfer and the delivery of fluids, and for each of these, a simplified model is used to analyse the gap between current and limiting performance. The wider systems of production require the co-ordination of resources and push at the limits of human biophysical and cognitive limits. Evidence about these is explored and related to current practice. Out of this discussion, five promising innovations are explored to show examples of how manufacturing speed is increasing - with line arrays of point actuators, parallel tools, tailored application of precision, hybridisation and task taxonomies. The paper addresses a broad question which could be pursued by a wider community and in greater depth, but even this first examination suggests the possibility of unanticipated innovations in current manufacturing practices.
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    Spatially resolved acoustic spectroscopy for integrity assessment in wire-arc additive manufacturing
    (Elsevier, 2019-05-15) Dryburgh, Paul; Pieris, Don; Martina, Filomeno; Patel, Rikesh; Sharples, Steve; Li, Wenqi; Clare, Adam T.; Williams, Stewart W.; Smith, Richard J.
    Wire–arc additive manufacturing (WAAM) is an emergent method for the production and repair of high value components. Introduction of plastic strain by inter-pass rolling has been shown to produce grain refinement and improve mechanical properties, however suitable quality control techniques are required to demonstrate the refinement non-destructively. This work proposes a method for rapid microstructural assessment of Ti–6Al–4V, with limited intervention, by measuring an acoustic wave generated on the surface of the specimens. Specifically, undeformed and rolled specimens have been analysed by spatially resolved acoustic spectroscopy (SRAS), allowing the efficacy of the rolling process to be observed in velocity maps. The work has three primary outcomes (i) differentiation of texture due to rolling force, (ii) understanding the acoustic wave velocity response in the textured material including the underlying crystallography, (iii) extraction of an additional build metric such as layer height from acoustic maps and further useful material information such as minimum stiffness direction. Variations in acoustic response due to grain refinement and crystallographic orientation have been explored. It has been found that the limited α-variants which develop within prior-β grains lead to distinctive acoustic slowness surfaces. This allowed prior-β grains to be resolved. A basic algorithm has been proposed for the automated measurement, which could be used for in-line closed loop control. The practicality and challenges of applying this approach in-line with fabrication are also discussed.