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Technology update
Time and cost savings
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Reducing aluminum and composites machining costs is a target for all aircraft manufacturers. Rye Technology's Pentaxial CNC aims to reduce the time and cost involved in final machining of large aerospace components to fine tolerances, particularly when complex shapes and curves are involved. The Pentaxial CNC is used for machining wing components, galley sections, helicopter rotor blades, and other large precision components. At Chevron Aerospace in the UK, the engineering team has achieved a major reduction in machining time on a large Airbus aluminum wing component by using a Rye Pentaxial for the latter stages of the process. Chevron manufactures the leading edge wing box for the A340-600.
Rye describes the five-axis machine as being about a third the price of a conventional machining center capable of handling an equivalent cube; machine time therefore costs less. The fast Pentaxial can be used for the final machining of such things as wing sections where relatively small quantities of metal are being removed, but fine tolerances and high speed are necessary. According to the company, using the Pentaxial in this manner frees additional time on the more expensive conventional machining center, which increases productivity and lowers production costs, while overall machining time per component can be reduced by as much as 75%. Typically equipped with twin-parallel tables and a BWO CNC 900 controller, the Pentaxial CNC router is available in a variety of configurations but usually has a 10-kW, 12-station automatic tool change spindle. The two tables run lengthways through a fixed bridge so that one can be loaded while machining takes place on the other. This can optimize cutting time and improve safety by keeping the operator away from the cutting area at all times. Alternatively, the tables can be synchronized to give double the working area as a single table. Feed speeds are adjustable up to 15 m/min and rapid positioning up to 20 m/min.
Chevron Aerospace supplies Airbus components to BAE Systems (formerly BAE Airbus). The first set of leading-edge components for the A340-600 was delivered last December. Keith Summers, General Manager of Chevron's Engineering Division, stated that experience in the early stages of the development process had shown that using a five-axis milling machine for the whole machining process took longer than anticipated. This was due to extensive detailed five-axis operations at the end of the machining cycle when the winding edges on the leading edge of the wing were created. Assessment showed that the power of the milling machine was not critical to this phase of the operation since little metal was actually being removed.
"We realized that we could speed up the whole operation dramatically if we could use a much lighter and faster five-axis machine for the final machining on the outer dimensions," he said. A Rye Pentaxial was installed. "Using the much higher speed of the Rye Pentaxial for the final stages of machining saves 75% of the total machining time for the leading-edge wing box."
Stuart Birch
Aerospace Engineering May 2000
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