Starting from a twin-spindle, twin-turret multi-axis lathe, an electric actuator company engineered a manufacturing system complete with tooling and programs for six components.
When Rotherham, UK-based Precision Magnetics launched an innovative electric actuator for the aerospace industry it took a bold decision. Even though it had no history of advanced machining it realised that it had to make these complex and sophisticated products in-house. Turning Technologies, the UK distributor for Nakamura-Tome and a member of the Engineering Technologies Group, provided the turnkey solution and support that made this possible.

Historically, Precision Magnetics had specialised in the manufacture of extremely powerful Neodymium Iron Boron (rare earth) magnets.

The materials had originally been developed for small powerful electric motors to be used in automotive components such as pumps and windscreen wipers and were also widely used in computer disk drives.

Until a couple of years ago, this was a significant part of the company's business, but the production route was becoming unsustainable in a global market.

The Neodymium ore from China was shipped to the US for refining into sintered bar that was sent to the UK for processing into magnets that were then sent to the disk drive manufacturers in Singapore.

The solution, a manufacturing joint venture in China, meant that Precision Magnetics had to look at new applications for the magnets.

Andrew Myers, managing director of Precision Magnetics, said that this move came as no surprise and the company was already looking to develop value-added applications that incorporated the magnets into more complex components, particularly for the aerospace sector.

Because these rare earth magnets are so powerful they can be used to make electric motors that, weight for weight, are much more powerful than hydraulic actuators.

This makes them particularly attractive for driving control surfaces such as ailerons, rudders and elevators.

But having sold the concept to its Tier One customers, Precision Magnetics then had to look at how it would be able to manufacture the actuators.

'We made the first ones ourselves by buying in the machined parts from a subcontractor,' said Myers.

'But when you sign long-term contracts, you get the benefit of long-term business, but you have to be able to offer year-on-year 'cost-downs.

To be able to maintain the business we had to take some of the cost out - and the biggest cost element was the bought-in components.

The only solution was to make the parts ourselves.' But these were complicated parts in difficult materials and there was no history of CNC machining within the company.

'We did not have any in-house skills so we had to find a partner who could offer us a complete solution,' said Myers.

'After researching the market and looking at a number of possible routes we decided that we wanted to work with Turning Technologies.' Turning Technologies was able to help because it had the right technology to produce the parts in one setting - which the required levels of accuracy demanded, but, perhaps more importantly, Precision Magnetics needed to be able to put its faith in a company that could take them on from basic toolroom machines to the latest multi-axis, 'one-hit' machining techniques.

Starting from a Nakamura-Tome WT-300 twin-spindle, twin-turret multi-axis lathe, it engineered a production-ready manufacturing system complete with tooling and programs for six components.

'They provided the best technical solution and it was based around a single machine.

That was important for us too.

For this application and with our lack of experience we were much happier having just one machine to concentrate on,' said Myers.

The machining requirements were extremely demanding.

The actuator shafts are manufactured from tough stainless steel and with a hollow internal diameter larger than the through bore, and the sleeves that go round them are even more difficult to make.

These are machined from solid inconel to a wall thickness of 0.5mm, so work-holding and handling are critical.

The slightest clamping problem could result in an expensive scrapped component.

As Richard Turner, managing director of Turning Technologies, explained, 'We had to develop a process using a hydraulic steady mounted on the lower turret, together with quick-release mandrels to suit various diameters of sleeve on the right-hand spindle so that we could finish machine the outside diameter to an extremely tight tolerance.

Because of the small batch sizes, changeover times are very important, so we put quick change chucks on both the spindles too.' With the system installed and in full production Myers said the whole project has been a great success.

'We have shown our customers we are investing in the supply chain and becoming a partner.