In 2008, Fred Hutton and Simon Burchett — two former production engineers at Formula One team Red Bull Racing — decided to start their own CNC machine shop specialising in the manufacture of composite patterns and moulds.
Called Freeform Technology, the company chose Buckingham — in the heart of the UK’s ‘motor-sport valley’ — as its base. Today, it supplies not only Red Bull Racing but also other F1 teams, including Lotus, Mercedes GP, Williams, McLaren and Marussia.
The fifth and latest five-axis machining centre to be installed at Freeform Technology’s 6,000ft
2 facility is a DMU65 MonoBlock five-axis universal machining centre from Coventry-based DMG/Mori Seiki
(www.dmgmoriseiki.com). Since 2005, this machine tool supplier has been an Innovation Partner to Red Bull Racing in Milton Keynes, which is where Messrs Hutton and Burchett first became familiar with the capabilities of the equipment.
Another DMG/Mori Seiki five-axis machining centre, configured with a B-axis spindle head and rotary table, has been in use for a couple of years at Freeform Technology, but the three other machines on site are from an Italian firm that provides equipment for light machining within a large working envelope. These are ideal for surfacing epoxy tooling block (also called model- or pattern-board), which at Freeform Technology forms a majority of the tools produced.
The patterns and moulds are used for manufacturing carbon-fibre-reinforced plastic (CFRP) body parts and other components on racing cars, such as the engine cover — and even the steering wheel.
The company also produces non-moulded parts; these include laminate under-floor ‘planks’ for racing cars, aluminium parts used in wind-tunnel tests, and a variety of jigs and fixtures.
High-quality work and fast turn-rounds have been key to Freeform Technology’s rapid growth in the motor-sport industry; first-hand experience of the sector has also contributed to the company’s success. However, Freeform Technology is now a victim of its own success, as it finds itself with 14 employees working ‘flat out’ from December to March (during the build up to the new F1 season), but with spare capacity during the rest of the year — hence the purchase of the latest five-axis DMG/Mori Seiki machine.
Unlike the Italian plant on site, this machine has the power and rigidity to tackle any material — including the toughest of alloys. Mr Hutton says: “It is not our intention to move into the manufacture of end-use metal components at the moment — even though we could — but to concentrate on what we know best and transfer our expertise in composite pattern making across to other industries. We have already produced front- and rear-bumper patterns for the Nissan RML Juke-R and the BMW WRC Mini. We see automotive as a growth area for us, as more and more CFRP parts are being incorporated into road cars, or at least offered as options. We also intend to offer mould- and pattern-making services to companies in the aerospace supply chain.”
The programming of jobs generally starts with a customer’s IGES or STEP file, which is imported into Freeform Technology’s Siemens NX8 CAD/CAM software to produce the tool-paths, some of which are very complex. Fully interpolative five-axis scanning cycles on the DMU65 MonoBlock produce fine surface finishes using mainly poly-crystalline diamond (PCD) tooling. The 18,000rev/min HSK-A63 spindle option was selected to maximise productivity when machining aluminium and tooling block, the latter being cut dry.
With a view to expanding into processing harder metals, an extra-large coolant tank has been fitted to deliver through-tool coolant. Other options included are a 30-position tool magazine, Blum laser tool-length measuring and tool-breakage detection, and Renishaw spindle probing for setting workpiece datums.
Mr Hutton says he likes the ±120deg swivelling trunnion of the latest DMG/Mori Seiki machine because, in his opinion, it is more versatile than a B-axis configuration, which is limited by its inability to achieve such a large negative angle. Furthermore, the machine’s compactness in the Z axis promotes efficient cutting cycles and reduces the risk of interference, although Freeform Technology uses Vericut simulation software before running a new program.
Five-sided working
In 1998, Andrew Russell and Stephen Boocock resigned from a sub-contracting company to establish their own — Progress CNC. Initially, they had a three-axis machining centre and no work; today they have a selection of manual and CNC machines for both turning and milling. They also have spark erosion equipment and offer a mould- and die-making service, along with reverse engineering based on the use of a co-ordinate measuring machine — and in January this year, Progress CNC considerably extended the range of its machining capabilities with the installation of a five-axis machining centre.
The German-built Spinner U5-620 — the first in the UK — was supplied by recently appointed sales and service agent Whitehouse Machine Tools Ltd, Kenilworth
(www.wmtcnc.com).The configuration of the 12,000rev/min vertical spindle machine places all the linear slideways above the working area. Rotary axes are provided by a 360deg 650mm-diameter table mounted on a -90/+110deg swivelling trunnion. Unusually, this axis runs from front to back, rather than adopting the more typical side-to-side arrangement. The non-driven side of the trunnion is supported at the front of the machine by a counter bearing to allow heavy milling and ensure high levels of accuracy.
The machine’s footprint is just 2,600 x 2,350mm, which is regarded as particularly compact for a machine capable of milling and drilling a half-tonne workpiece in a nominal 0.5m-cube working volume. Moreover, hydraulic clamping, glass scales, a swarf conveyor, a 32-pocket tool magazine and a high-pressure coolant pump are included as standard. Control is via a Heidenhain TNC 620 contouring CNC system.
Mr Russell says: “The Spinner’s specification far outweighed that of other five-axis machines we considered — plus the machine was cutting metal on the first job within 48hr of being commissioned; and thanks to the use of glass scales, we are holding very tight tolerances.”
Mr Boocock added: “Andrew and I went over to see the Spinner factory, where the machine tool builder uses its own lathes and machining centres to make many of the constituent parts. The owner, Axel Spinner, took time out to meet us and take us to a nearby job shop that uses a U5-620 five-axis machine so we could see how it would fit into our operation.”
Progress NC is an archetypal jobbing shop, producing parts for aircraft, boats, guns, motor-sport and a wide variety of other industries. Batch sizes range from single items to 100. An early job put onto the U5-620 was an aluminium part for the top of a mast on a £30 million ocean-going yacht competing in this year’s round-the-world race. The part required all five axes to be interpolated simultaneously to generate complex surfaces, which were programmed quickly from the customer’s CAD model using five-axis software added to Progress NC’s existing OneCNC CAD/CAM system.
Other jobs require repositioning the component in one or two rotary axes, which are clamp-ed while machining is completed using the three linear axes. One example was a 0.5m-long steel tow bar (for a commercial vehicle) that would have been, according to Mr Russell, a ‘nightmare’ to produce on one of the firm’s three-axis machines. Another 3+2 machining contract involved producing a steel injector flange for a diesel truck from 316 stainless. The part was machined in two operations on the Spinner; it would have needed five operations on a three-axis vertical machining centre. The time saving was significant, as a batch of 20 parts was required; and because fewer fixtures were needed, work-holding costs were reduced.
The use of machining strategies that involve positioning of the rotary axis was the principal reason for Progress NC opting to move into five-axis machining. However, preparing cycles off-line that interpolate all five axes simultaneously was easy to learn, according to Mr Boocock, who describes the company’s entry into the technology as being quick and straightforward.