On-machine probing vital to "done in one" processing of aircraft parts

Dunlop Aerospace Braking Systems, a part of Meggitt, designs, develops and manufactures wheels and brakes for commercial and military aircraft. To meet steady growth in demand, Dunlop created a hub and flange cell at its Coventry, UK plant built around three state-of-theart CNC machine tools capable of multiple operations and multi-face/axis processing without refixturing. Key to a "done in one" production strategy, all the machines were specified with Renishaw probing systems.

Dunlop invested over $3 million in machine tools capable of high versatility and automated processing efficiencies. These include: a multi-tasking Mazak Integrex, a turning center with full C-axis and driven-tool milling capability; a large Mazak HV800 five-axis horizontal machining center; and a Mori Seiki MT4000 multi-function turning/ milling center, the first of its type in the UK with 30-in. turning diameter, 40hp milling spindle and 60-tool ATC.

Renishaw probes, carried in the tool magazines, are used to locate the part on setup, to identify and correct for stress relief changes, to enable in-process measurements and compensations, and to automatically reset machine coordinates for changing processes, axes and part faces without operator intervention.

That process control allows Dunlop to produce wheels and brakes that are reliable in all conditions and scenarios, while meeting aviation industry demands for ever-increasing accuracy and quality.

Wheels are machined from aluminum forgings, usually L77 aluminum. The high cost of components makes it essential that Dunlop Aerospace keep scrap levels low.

Probes are used to check the forging for irregularities during setup, creating best-fit location of the part. This eliminates air cuts, lets metal cutting start immediately and ensures that critical surfaces are accurately located, while reducing overall cutting time.

Touch probing allows for resetting of the machine coordinate system relative to previously machined features, vital to process consistency when indexing the part, changing machining axis angle, or switching processes, such as from turning to milling on a multi-tasking machine.

The integration of probing into the machining process helps Dunlop to design for manufacture in its new product introduction process.