Five-axis machining for cylinder heads By mounting cylinder heads in trunnion fixtures which rotate below the swing centreline, they can be rotated about the axis of the cutting tool, minimising the d

By mounting cylinder heads in trunnion fixtures which rotate below the swing centreline, they can be rotated about the axis of the cutting tool. This arrangement minimises the degree of swing and so develops excellent cutting dynamics, says Hermle. The above is seen by TWR Engines' manufacturing manager, Simon Lockwood, as one of the main benefits of using a Hermle C800U five-axis machining centre.

'It is a feature that helps us to further reduce cycle times and ensure accuracy,' said Lockwood.

TWR's Kidlington, Oxford plant produces engines for the Arrows Formula 1 cars and Volvo BTCC cars among others.

Company restructuring has seen TWR performing more machining in-house, which meant acquiring flexible machining centres.

Around 100 Arrows F1 engines/year are made and the cylinder heads feature compound angle valve guides and seats.

Timescales can be only four weeks from initial production engineering to final machining.

The Hermle C800U1s features of a fast 30-tool toolchanger and 5m/s2 axes acceleration to 35m/min help reduce non-cutting times.

Surface finishes achieved are within 0.8mm and positioning accuracy is within 0.008mm.

TWR Engines apply the Hermle machining centre to any 3D surface work requiring a high quality finish.