GTR Composites is finish machining large carbon fibre composite components to tolerances measured in the tens of microns.
Headquartered in Fontwell, West Sussex and operating from four sites near the south coast of England, GTR Composites is probably best known for supplying Formula One teams with high quality carbon fibre components and assemblies.
Today it is also expanding its activities in all kinds of automotive special projects. The highly specialised subcontractor has produced lightweight chassis and other large parts from composite materials for a long time, but at the beginning of 2021 it started final-machining them to tolerances measured in tens of microns.
The introduction of this new service followed the installation of a Zimmermann FZU400 5-axis machining centre at its Bognor Regis facility.
Supplied by UK sales and service agent Kingsbury, the portal machine has a 4,000 x 3,000 x 1,250 mm working envelope and the ability to hold high levels of accuracy.
For example, a positional tolerance of 50 microns is achieved on features across a full chassis, while holes and counterbores are held to within 10 or 20 microns. As the components being produced are of high value, GTR adopts a policy of having an operator permanently in attendance, even when the FZU400 is running overnight.
Simon Kingdon-Butcher, joint owner of GTR said, "The investment has allowed us to expand our business not only in the motorsport sector but also on special projects and into more production chassis work for road-going supercars. We are presently producing 14 chassis for the research and development phase of such a vehicle.
"The Zimmermann machine stood out in terms of its rigidity, which translates into the tight tolerances we are able to hold when cutting carbon fibre. We’re able to impress our customers by hitting really tight limits that our competitors cannot achieve. This investment has quite literally moved us ahead of the rest.
"High spindle power - 34 kW continuous / 41 kW peak - enables us to rough aluminium moulds, while spindle speeds up to 24,000 rpm means their surfaces can be finish-machined to very high quality using minimum quantity lubrication.
"MQL also enables us to mill and drill carbon fibre components containing titanium or aluminium inserts in the presence of a specific type of coolant approved by our customers."
He added that their other large capacity 5-axis machining centres are focused on pattern making and while carbon fibre can be cut on them, the parts would typically be of less demanding accuracy than the Zimmerman FZU400 is capable of delivering, despite its much larger working envelope. However, the machine is also used for large pattern work and he regards the versatility of the new capacity as an ideal fit for GTR.
The company is no stranger to making big components in large quantities, having produced 250 chassis in recent years for the MoD's Foxhound patrol vehicle. Transition to final machining of larger structures and assemblies in carbon fibre, which entails cutting cycles of up to 60 hours, is therefore proving seamless for the subcontractor. The addition of production volumes for supercars is seeing work for the motorsport sector, although remaining at a constant level, fall gradually from 90% of turnover to probably around two-thirds as the company expands.
A video of Simon Kingdon-Butcher speaking about the installation of the Zimmermann FZU400 at GTR Composites may be viewed at: https://kingsburyuk.com/video/gtr/
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