Once renowned for its heavy engineering prowess, the UK's manufacturing sector is regaining a reputation for large scale machining after a period of transition. Machinery reports
Where heavy engineering in the UK once entailed shipyards and steel mills, a period of change has seen the sector re-emerge in a more high-tech guise. Today, heavy engineering shops are more likely to be making parts for power generation, oil exploration, yellow goods, large machinery and aircraft wing contracts than for submarines or smelting plants.
According to Heller Machine Tools (0121 275 3300), many machine shops seeking heavy duty solutions opt for horizontal machining centres, a decision based on factors such as machine robustness and power.
Heller offers horizontal machines with up to 3 m of capacity in the X-axis and typical of its large/heavy engineering installations is Rochdale-based Chelburn Precision Ltd, a sub-contractor supplying to sectors such as oil and gas. The company has installed two Heller MCH 460 machines with 4 tonne capability on the tables. Torque is 822 Nm, while travel in the X and Y axes is 2,000 and 1,600 mm, respectively. Quality, robustness of machine and capacity were the over-riding factors in selecting the Heller horizontal machining centres, rather than conventional borers.
"The Hellers have galvanised our market position by enabling us to offer large, complex component machining within short lead times and at competitive costs," says Ken Ackers, business development manager at Chelburn.
Another sub-contract specialist in large parts machining is also expressing its preference for horizontal machining centres. Burgess Hill-based HPC Precision Engineering has recently installed a Makino A100 twin pallet, 4-axis model of 1,700 x 1,350 mm capacity. Supplied by NCMT (020 8398 4277), the machine has been added to two similar machines in a flexible manufacturing system (FMS) that produces structural fuselage components for aircraft such as frame supports and bulkheads.
NUCLEAR KNOWLEDGE
The nuclear industry is certainly generating plenty of activity in the UK at the moment, thanks largely to the €5 billion ITER (International Tokamak Experimental Reactor) project. MG Sanders of Stone in Staffordshire, for example, has recently won a contract to supply components for JET (Joint European Torus), a science and technology feeder project for ITER.
To help fulfil its obligations, the company is using a recently installed Toshiba BMC800 horizontal machining centre, supplied by Leader CNC (024 7635 3874). The twin-pallet BMC800 can process components measuring up to 1.5 by 1 m, with the special Inconel billets it machines costing anything from £3,000 to £10,000 per block.
The same company has also invested in a large vertical machining centre in the form of a 4-axis Mikron VCE 1600 Pro from GF AgieCharmilles (024 7653 8666).
Elsewhere, heavy machining specialist DavyMarkham of Sheffield also has an interest in ITER. In fact, the company is now part of a consortium bidding for the construction of the main reactor vacuum vessel of the ITER nuclear fusion reactor being built in Cadarache, France. The consortium comprises Davy Markham, precision fabricator Metalcraft of Chatteris, engineering consultancy AMEC and The Welding Institute (TWI).
Europe and Korea are building the ITER vacuum vessel, which consists of nine D-shaped vacuum vessel sectors, each weighing about 450 tons. Its external diameter will measure 19.4 m, with an internal diameter of 6.5 m, and once assembled, the entire structure will be 11.3 m high. Fabrication tolerances for the whole vessel, including field assembly, are expected to be less than 20 mm for both height and width. When all of the vacuum vessel's shielding and port structures are included, it will weigh in excess of 5,000 tonnes.
Europe is providing seven vacuum vessel sectors, with the remaining two supplied by Korea. Contracts for the ITER vacuum vessel are likely to be placed later this year or early in 2010.
Kevin Parkin, managing director of DavyMarkham, explains the background to the consortium: "The ITER vacuum vessel is a significant engineering challenge that no single company is capable of supplying," he says. "So we've put a consortium together with fabrication specialist Metalcraft, AMEC providing design and programme management services, and TWI offering technical support, to enable us to present a solid technical and commercial case."
DavyMarkham is, of course, no stranger to producing such sizeable parts. Earlier this year, the company secured a $20 million order for the supply of mining hoists for gold producer IAMGOLD Corp of Toronto, Canada. The contract includes the largest double drum hoist supplied to North America in recent times, with a diameter of 6.4 m, a drum width of 2.4 m and a payload capacity of 20 tonnes. It will serve as the mine's main production hoist, operating at depths down to 2,652 m.
To help fulfil such contracts, DavyMarkham has accumulated extensive heavy machining capacity. In fact, its largest machine bay comprises of a machine bed that covers half of its entire floor area (34.5 by 14.7m). CNC ram borers surround this huge bedplate, enabling very large workpieces to be machined.
Most of these ram borers are Asquith models, with X-axis capacity up to 14 m. Today, incidentally, Asquith Butler machines are produced at purpose-built premises in Brighouse, West Yorkshire (01484 726620), where the largest machine manufactured to date has a 30 m X-axis and is being used for the manufacture of TGV coach panels.
BIG PARTS; BIG MACHINES
Any form of mining or exploration at depth usually entails the design of large, robust components, which, in turn, requires machine tools with similar attributes to carry out manufacture.
A case in point is Glenrothes-based sub-contract specialist KSW Engineering, which has recently installed a new Doosan DB 130CX horizontal borer, supplied by Mills CNC (01926 736736), to machine large parts for the oil sector, such as wellhead housings.
The DB 130CX travelling column machine boasts large X, Y and Z-axis travels (4,000 by 2,000 by 2,000 mm), all fitted with linear scales to optimise accuracy. The machine has a high torque spindle (25 kW), with a three-range gearbox for heavy duty machining and fast metal removal rates.
Sometimes the machine tool industry can generate its own demand and such was the case recently at the Worcester headquarters of Yamazaki Mazak (01905 755755), where the company had identified the need to increase its capacity for large castings for its machine tool beds and columns. The solution arrived in the shape of one of its own Versatech V-100N models – the only one of its kind in the UK.
"We use our Versatech to machine the beds and columns for the range of machine tools we manufacture here at Worcester," says Richard Austin, Yamazaki Mazak's general manager - direct production. "By making use of the new features on the machine, we can reduce cycle times by as much as 20 per cent. These are significant savings when you consider that some of our machine beds can be on the Versatech for between five and six hours."
Among the many new features introduced with the latest range of Versatech machines are a high speed spindle, a fully CNC universal head, high pressure through-spindle coolant and a table change system that allows the Versatech to be integrated into an FMS.
Image: Mazak is using its own machines to make machines – a Versatech, seen here machining bed castings
"The universal head gives a significant advantage where the process demands both horizontal and vertical approaches to the machined faces. The fact that this head can, within a matter of seconds, change orientation, without the need to change heads, saves considerable amounts of time," says Mr Austin.
Positioning and accuracy of the up to 10,000 mm long bed (V-140N) is controlled by moveable servomotors positioned on the ballscrew nuts of the X and Y axes. In the X-axis, linear guides and twin ballscrews provide the high response rates and positional accuracy required. This combination also delivers rapid traverse rates of up to 30 m/min (V-100N) and high rates of circular interpolation. Accuracy is aided further by the addition of temperature-controlled oil through the cores of each ballscrew, minimising thermal distortion, due to high speed operation of the machine over extended periods.
The machine installed at Yamazaki Mazak's Worcester facility is also equipped with an optional two-table changer system.
"The previous machine had a pallet changer, so we are not seeing major productivity improvements with this system. However, one advantage is that the new system can be integrated into an FMS, if required. This is something that is already in place at one of Yamazaki Mazak's factories in Japan," concludes Mr Austin.
Big in Holland
Dutch machine tool builder Unisign (0031 773 073777) says that its recently launched Unicom 8000 CNC machining centre is the largest ever built in the Netherlands. It has X, Y and Z axes of 3,600, 3,300 and 1,600 mm, respectively, while height below the bridge is 2,300 mm; width between columns 3,000 mm.
The first Unicom 8000 is for Unisign customer Habets in the Netherlands and will be used to produce planetary gear carriers for a wind turbine supplier. The second machine has already been ordered by automation and power specialist ABB of Switzerland
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