Hermle five-axis machining centre

Citation

(2000), "Hermle five-axis machining centre", Aircraft Engineering and Aerospace Technology, Vol. 72 No. 1. https://doi.org/10.1108/aeat.2000.12772aab.005

Hermle five-axis machining centre

Keywords Hermle, Machining, Components

TTL, considered an authority on adaptive manufacturing of 3D variable geometry components, has taken delivery of its second Hermle C800U five-axis machining centre from Traub-Heckert UK Limited. It is being used in the development of TTL's adaptive machining systems for the gas turbine industry. One of the machine's first "duties" was to demonstrate this technique on the TTL stand at last year's Paris Air Show.

Variable geometry components are a major problem in the gas turbine industry. Whether parts such as turbine and compressor blades, nozzle guide vanes and combustion chamber are being manufactured new from forgings or casting or being repaired, their exact geometry is not known. TTL's solution is its adaptive machining method for which a precision five-axis machining centre is believed to be necessary. The "vehicle" chosen for this process is the Hermle C800U.

To demonstrate its method at the Paris Air Show, TTL chose one of nature's own variable geometry components - a hen's egg. This was engraved half way into its shell, and without breaking through, on the five-axis Hermle (Plate 3). The demonstration then switched to machining a welded compressor blade tip in which the excess weld is removed to leave it perfectly blended with the aerofoil, without removing parent material. This TTL blade repair technique is said to be able to bring the blade back into conformity accurately and automatically in about one minute, despite the variations in chord width and weld thickness of the blade being repaired.

Plate 3 A high-precision Hermle C800U five-axis machining centre engraving a hen's egg at the Paris Air Show

The TTL solution involves three stages. In the first the repaired blade tip is automatically scanned to an accuracy of ±10µm on the Hermle using an infrared wireless probe. In the second TTL software captures the data from the probe, creates a true 3D surface model, generates the tool paths and performs post-processing, all without manual intervention. The final stage is machining on the Hermle with the generated program that is unique to each blade in the batch.

The Hermle C800U is thought to be fast becoming a standard five-axis machining centre with aerofoil blade manufacturers. Over the past 12 months Traub-Heckert UK reports that it has supplied a total of 13 of these machines to companies involved in the manufacture of turbine and compressor blades for gas turbines. Like all the Hermle CNC universal milling machines and machining centres, they are fully supported by Traub-Heckert UK. Its service extends from trials, applications engineering and full prove-out at the Brackley Technical Centre to spares supply and after-sales support including a wide range of planned maintenance schemes.

Details available from: Traub-Heckert UK Limited. Tel: + 44 (0)1280 705482; Fax: +44 (0)1280 705606.