A Renishaw probe checks an aerospace wheel at Dunlop Aerospace.
For its done-in-one production strategy, Dunlop Aerospace Braking Systems, a manufacturer of aircraft wheels and brakes, invested more than $3 million for a cell of machine tools capable of multiple operations and multiface/axis processing without having to refixture. And, to optimize its production strategy, the company equipped all the machines with probing systems.
Each machine's tool magazine carries a Renishaw Inc. (www.renishaw.com) probe that is used to locate parts during set up, to identify and correct for stress-relief changes, and to conduct in-process measurements and compensations. The probes also allow the machines to reset their coordinates automatically for changing processes, axes and part faces.
"We have now used the probing systems for over six years and have cut costs and times, with a step change in process control and consistency," said Andrew Cartledge, team leader of Dunlop's (www.dunlop-aerospace.com) hub and flange cell. That process control lets Dunlop produce wheels and brakes that are reliable in all conditions and scenarios, while meeting aviation industry demands for ever-increasing accuracy and quality.
Operators use the machining cell to produce aviation wheels from aluminum forgings, usually L77 aluminum. The machining cell consists of a multi-tasking Mazak Integrex turning center, a Mazak five-axis HV800 horizontal machining center and a Mori Seiki MT4000 multifunction turn-mill center. The high cost of the components – between forging and machining operations – makes it essential that Dunlop keeps scrap rates low. It does that by using the Renishaw probes to check forgings for irregularities during set up. This not only makes for the best-fit location of parts, but also eliminates air cuts, gets metal cutting started immediately and ensures that critical surfaces are accurately located, while reducing over-cutting time.
Machining often relieves stresses in the forged material, and the probes monitor for resulting dimensional changes for closed-loop automatic compensation the machine does itself. With touch probing, Dunlop also can reset its machine coordinate system relative to previously machined features. This is vital to process consistency when indexing parts, changing machining axis angles or switching processes, such as from turning to milling on a multi-tasking machine.
In addition, probing integrated into machining helps Dunlop design for manufacture in its new-product-introduction process. "We've seen improvement in machining cycle times every time we've introduced a component to the cell," said Cartledge.