Case Study

Scottish importer decides to make its own submarine goods

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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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