Case Study Scottish importer decides to make its own submarine goods

Editor: Eric Culp

Bowtech Products was established 22 years ago as an importer of articles used for underwater applications. Now the company designs and produces its own equipment.

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Scottish underwater components supplier Bowtech has realised that making tooling in-house can save time and money.
Scottish underwater components supplier Bowtech has realised that making tooling in-house can save time and money.
(Source: Hurco)

Exports at Aberdeen, UK-based Bowtech Products account for two-thirds of turnover, which has helped to double the size of the company's business over the last five years, one reason it won the Subsea UK Global Export Award 2012, sponsored by Scottish Enterprise.

Manufacture of components has historically been subcontracted but is gradually being brought in-house to control costs and quality as well as to shorten lead times from weeks to days. Two CNC lathes and a machining centre from Hurco are said to underpin this activity at Bowtech's production facility on the Kirkhill Industrial Estate in Dyce.

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Typical batch size is 100-off, which is now more economically produced on-site, while small runs and prototypes are machined much less expensively if sent to external machinists.

Cameras and LED lights core Bowtech products, particularly those mounted on remotely operated underwater vehicles. Business has been brisk enough for the addition of internal capacity to reduce subcontracted manufacture; Bowtech's new, dedicated machine shop is slated to open in 2013.

Cutting lead time by making mould tooling on site

Meanwhile, the Kirkhill unit leads the way within the group for bringing machining in-house. The division mainly makes polyurethane joints that connect submerged electric cables. Injection mould tools for the joints are made on a Hurco VM1 vertical machining centre, which was installed in 2009.

Stuart Rowley, Bowtech's cable and mechanical moulding manager, said, "After I have designed the two halves of a tool, production takes two to three days on the Hurco, whereas lead time was much longer when we had the mould made outside." Before the purchase, he said Bowtech had examined a similar machine at one of its suppliers, which was making mould tools for underwater electrical connectors.

"We realised that the WinMax software in the Hurco control was ideal for small quantity mould production," he said. "To maximise its effectiveness, we bought the manufacturer's 3D Mold package and practically every other software option."

In 2012, the success of this first in-house machining venture encouraged Rowley to consider making camera and light housings on site, which need a lot of drilled and tapped holes on the ends of round components, so it chose the Hurco TMM10 CNC turning machine with 10-inch chuck and driven tooling. It runs Windows software similar enough to the milling version that Bowtech staff could forego the training that came with the lathe purchase.

The company recently added a Hurco TMX8MY lathe with 8-inch chuck capacity. It has a Y-axis for off-centre cross-drilling of holes and milling of flats, functions not possible on the TMM10.

The company tends to pick higher added value work to turn-mill in quantities of up to 100-off. Larger runs, which can be as high as 1,000-off, are still subcontracted. Materials range from anodised aluminium to stainless steel to titanium alloy for the high value products. Typical accuracies are quoted at 0.125 mm total, although some O-ring grooves need tolerances of 0.025 mm.

A next step for Bowtech could be to consider 5-axis machining for complex titanium components since castings are expensive. Such work can also be costly if subcontracted.

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