Core values: traditional British engineering skills are still in demand, as Lee Hibbert found when he visited a firm that has just completed a design-and-build job on a giant scale.
Amid all the economic doom and gloom, it s easy to forget that there are still British engineering firms successfully competing in the global market. And some, like Bath-based Seward Wyon, are involved in some fascinating projects that are truly gargantuan in scale.
The heavy mechanical engineering firm has just completed an order for the design, manufacture and installation of an enormous rotating table, which is to be used as the base platform for the construction of transformer cores weighing up to 250 tonnes. Seward Wyon beat off competition from around the world for the 1.5 million [pounds sterling] project, reflecting its growing reputation as a serious player in the niche market for very large automated equipment.
Andrew Kemish, Seward Wyon's engineering director, says: "There are not too many British companies who can offer full turnkey packages on this sort of scale. The client wanted a table that could take the enormous weight of the transformer cores to the tightest tolerances, but with high levels of adjustability. Our ability to handle the bespoke nature of the work was deemed very important."
The work was carried out for Smit, the Dutch manufacturer of transformers for the power markets. The process of building the core at the heart of the transformers remains somewhat labour intensive: 0.3mm steel sheet laminations are laid up by hand while the core is fixed in a horizontal position. The core is then varnished before being rotated through 90[degrees] to the vertical for additional finishing work. Accurate core alignment is absolutely critical for the efficiency of the end product--so the table needed to have less than 4mm deflection with a full 250-tonne load.
"The table needed to be stiff but strong and capable of cradling the cores securely to ensure no movement during the rotational process" says Kemish. "The client produces different size transformer cores, so the table also needed to be fully adjustable across its range. We also had to take account of where workers would stand while the core construction was taking place. Ergonomically this represented something of a challenge--initially we wanted to put steel where Smit would need to put its people."
Seward Wyon's design engineers set about their task, primarily using Solid Edge CAD software. The table they came up with is essentially a large structural steel jig, measuring 11.5m in length and 8m in width, with associated fixtures. The table features a reduction planetary gearbox system and two 2.5-inch pitch Renold chain drives. It is electrically powered through a 35kW motor, turning on a large radius with PTFE bearings through 90[degrees] in less than three minutes.
As it rotates, the loads transform to a different part of the structure without any noticeable movement to the piece. When the work is finished, the transformer core is uncoupled and slid away using a compressed-air pallet.
The table was manufactured from start to finish in less than four months, and was tested in the UK before being shipped in parts on low-loaders to Smit's manufacturing facility in Nijmegen. Seward Wyon's mechanical fitters then put it together again on site in 10 days.
Kemish says that the project was completed on time and to budget, without any major hitches. "The design was fluid right until we started building it--so it proves that we are a very adaptable outfit," he says. "It's quite rare these days to find a firm that can cope with designing, fabricating, manufacturing and commissioning a structure of this size. But it goes to show that there is still a demand for traditional British engineering skills:
A follow-on order from Smit for an additional two transformer core build tables, which will be joined together to form one longer bed, is in the pipeline. That is expected to present Seward Wyon's engineers with additional control challenges as they bid to ensure that the tables rotate together in unison.
Other interesting contracts are also on the horizon. Seward Wyon has designed and built a variety of large structures for Airbus and is currently involved with the development of a jig for the A350 nose landing gear which will be installed at the aircraft maker's Filton plant in Bristol. Seward Wyon is also doing the consultancy on a large boom for an oil rig off the coast of Angola. "Not having all our eggs in one basket has served us well," says Kemish. "It might be tough but there is work out there."
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|Title Annotation:||AUTOMATION FOCUS; Seward Wyon engineers|
|Publication:||Professional Engineering Magazine|
|Date:||May 20, 2009|
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