Case Study

Nakamuras take on tough one-hit machining for JHE

Three Nakamura-Tome WT300 twin-spindle, twin-turret turning centres are helping John Huddleston Engineering (JHE) in Blackpool provide strategic support to Tier One and Two aerospace customers.

“Because we want high volume, and because there is quite a high degree of competition from the Far East, wherever possible we would want to make products in a single hit,” says Operations Director Ian Gibson. “The benefit that the Nakamura machines give us is that, as far as possible, we are able to produce a finished product on the machine without any manual intervention.”

The Lancashire company, which was bought by JHE in 1997 used to be a traditional jobbing shop providing tactical support to its customers, but, as Ian Gibson explains, the company has developed to become a strategic supplier.

“Most of the work we do is on longer term contracts and, as well as manufacturing, one of the key things we now provide is a supply contract whereby we hold stocks of parts here and we supply those parts to the customer on a direct line feed basis. We manage the stock in the customer’s plant, check the Kanbans and replenish them as required,” he says.

The components JHE produces include undercarriage parts and structural parts for wing and airframe assemblies for customers that include Spirit Aerosystems and Messier Dowty. The components are predominantly produced in hardened and tempered high strength steels using machining operations that include turning, milling, mill-turning and grinding.

As a lot of the work is for higher volume aircraft, such as the single-aisle A320 family, the overall production requirement is fairly high, but there is quite a lot of variation in the parts that go through the shop during a week.

As Machine Shop Manager Andy Wadsworth explains, “Some of the components are quite complex and require a lot of milling, but that has now been eliminated as a separate operation. It is all being done on one machine. We have got rid of queuing between operations and, because we are only loading the part once, we have increased accuracy too.”

One locking pin, for example, required three separate milling operations, three turning operations and two grinding operations. All the milling and turning is now done in one setup on the Nakamura. What’s more, the power and accuracy of the machine have removed the need for one of the grinding operations.

“With a twin-turret machine you can be machining two parts simultaneously, and that gives us quite a significant benefit in terms of cycle times too,” adds Ian Gibson.

The WT 300 machines have a through-spindle bar capacity of up to 100mm and a maximum turning diameter of up to 300mm. Each turret can hold up to 24 tools – including 12 driven tools – and a Y-axis on the upper turret allows sophisticated machining operations.

One aspect of the Nakamura machines that is particularly important to JHE is their machining power.

“The power of the driven tooling is quite exceptional,” says Ian. “About 95% of the work we do here is on high-tensile steels, and most of the time we will be machining in the fully hardened and tempered condition, so you have to have a lot of power to be able to do that kind of work.”

“It’s very tough stuff, and you also need a high degree of rigidity to get the best out of your tooling,” adds Andy Wadsworth.

The machines can cope with interrupted cuts too, he says. Machining slots on A340 wheel nuts, for example, involves two break-outs that create a lot of vibration. “If the machine isn’t up to it that can quickly take the edge off the cutter and reduce accuracy. The Nakamuras have more than enough power and rigidity to absorb that interrupted cut so you get better tool life.”

Ian Gibson says that JHE is very happy with the machines and that it was the right investment decision.

“Our company is looking at increasing the technology that we apply to the manufacture of product across the board, so we are going for multi-axis, high-speed, highly capable machines When we got our first Nakamura WT 300 in 2005 we knew it would provide us with a lot of benefits but it surpassed our expectations. Not only did it make the parts we planned to make, but it was controlling them to such a high standard that we were able to do away with some operations, such as grinding, and the Y-axis let us deburr parts on the machine, cutting out another operation. Altogether we found it a very productive machine. On the strength of that we decided we could transfer more of our work onto this type of technology and achieve a similar productivity improvement.”

JHE’s second WT 300 was installed in April 2006 and the third followed three months later.

“We have completely transformed the majority of work in that area, replaced our existing equipment with Nakamura technology and seen significant in cycle time. This allows us to remain competitive,” says Ian.

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For more information please contact:

Jarrod Christie-Smith
Turning Technologies
Tel: 01926 818 418