County Down based Crossen Engineering is working with a US gas turbine refurbishment company to develop a new method of producing aero engine air seals. Instead of being rolled, they will be pressed using a tool machined on one of its Hurco vertical machining centres
This year, 4,000 such seals will be produced in the press shop at Newtownards, which has 17 power presses rated from 35 to 500 tonnes force for subcontract production runs of progression and deep drawn components.
The contract has boosted the proportion of aerospace sector work done by Crossen Engineering to 20 per cent of turnover. The company received AS9100 quality management accreditation in 2010 and intends to grow the aerospace side of its business further to 75 per cent by 2015.
Another recent aerospace project, for University of Ulster spin-off, LenisAer, Belfast, was to design a press tool for forming a sector for an engine nacelle lip skin from a sheet metal blank, currently aluminium but perhaps also titanium.
Pressworking contracts carried out in other industries include making a tool and supplying hood reinforcement parts for lift trucks; and tools used in the production of the Audi A8.
Started in 1978 to service a local need for press tools, the firm moved into the manufacture of steel and aluminium mould tools in the mid 90s. It gradually established an injection mould shop which now has machines from 60 to 500 tonnes clamping force to fulfil subcontract runs in short lead times. Today, the split between press tool and injection mould work is roughly 50:50.
A recent success was winning back a contract previously lost to China, namely tool manufacture and production of plastic moulded parts used in flat-pack kits for polling booths and ballot boxes marketed by Pakflatt in Derry. Another injection mould, machined on a Hurco VMX42, is for producing parts for ABS dummies assembled by a Belfast company, Trucorp, for resuscitation training.
A customer in receipt of both mould and press tools together with the plastic and pressed parts is roof window manufacturer, Keylite, Cookstown.
The company acquired its first Hurco, a BMC40, 25 years ago. “The machine gave 20 years of excellent service, cutting a range of materials including prehardened steels, and although not currently in use, it is still operational,” says Paul Crossen
In the last six years, the company has installed four VMX42s, the latest in April 2011, and a VMX64 from Hurco to increase the size of parts that can be machined in-house. All are 40 taper machines.
The first VMX, with 12,000rpm spindle, arrived in 2005 to produce aluminium injection moulds for manufacturing rubber mats for cars. Suppliers to Porsche, Mazda, Kia and Mercedes Trucks number among the many users of these moulds.
One of the other VMX42s has a higher speed spindle capable of 15,000 rpm. It was bought to concentrate on machining of aluminium parts for aircraft, such as seat supports and trim, as well as to produce vacuum forming tools. The VMX64, with its 1,626 x 864 x 762mm working envelope, was acquired in 2009 for machining bolster plates and other larger components whose production was previously subcontracted. A similar machine will replace the BMC40 at the end of 2011.
Programming efficiency at Crossen Engineering is just as important as machining time. In this respect, Winmax software in Hurco’s latest Ultimax control is proving beneficial.
Although it is possible to use the conversational capability to program relatively complex 3D shapes on the shop floor, this is mainly done in Delcam Powermill and downloaded. Programming of 2D shapes is well within the control’s remit, but again, the toolmaker tends to do this in Autocad and send a DXF file to the Ultimax, which is able to read the data directly. The rationale is to eliminate human error. Conversational capability in the control is used to prepare some simpler programs. The software also provides flexibility for editing programs quickly on the shop floor, without having to return each time to the office CAM system.
One operator runs two Hurco machines at Newtownards over a single shift at present, so there is plenty of capacity to ramp up output, if order levels dictate. Nevertheless, Crossen Engineering already benefits from production hours after each manned shift, as one or two machines routinely are left to run unattended overnight and at weekends. Some jobs, such as profiling of the car mat injection moulds, continue largely unattended for 48 hours.
