For machining its high-performance motorcycle engines from solid billets, R&R Cycle relies on Mori Seiki NH5000s.
R&R Cycle runs pallets with tombstones on its Mori Seiki NH5000s to quickly respond to urgent customer needs.
High-performance motorcycle-engine builder R&R Cycle in Manchester, N.H., differentiates its product by being the only manufacturer in the country producing full-billet engines. While these engines result in superior performance as compared to those made from pre-formed castings, they do require more machining at tight tolerances, which R&R accomplishes on two NH5000 Mori Seiki machining centers. These rigid machines let the shop hold tolerances to within 0.0005 in., unlike its previous machining centers. They rested on individual feet, and as temperatures changed with the seasons, the shop's shifting concrete floor caused part inaccuracies.
With rigid bodies and special tri-bases, NH5000s perform as if level, even when placed on surfaces that aren't. In fact, they hold tolerance so well that R&R has eliminated most of the gaskets and O-rings from its engine designs.
Extra machine rigidity also means increased feedrates without sacrificing accuracy. When cutting a set of cylinder heads on its old machines, R&R had to keep a 2-in. shell mill feeding at 80 ipm to hold tolerances. Using the same shell mill on the NH5000s, however, boosted that rate to 450 ipm. Then after switching to a new Valenite shell mill, the shop raised feedrates to 550 ipm and reduced cylinder-head machining time from over 15 hr to less than 5 1 /2.
R&R also minimizes its setup times using the standard automatic pallet changers (APCs) on the NH5000s. The shop runs pallets with tombstones, and rather than touching-off on individual jobs, it programs with the center of rotation as absolute zero.
Tombstones are designed for specific jobs, and when one begins, the machines automatically touch-off the tombstones to identify which program should run. Then they touch-off on the parts to ensure proper loading. If parts are misloaded, the machines signal operators. "These simplified setups save us a lot of time," says Reggie Ronzello, Jr., co-founder of R&R. "And it wouldn't be possible without the repeatability of the NH5000s."
In addition, running pallets with tombstones provides much needed flexibility to quickly respond to urgent customer needs. "Changeovers are fast with the Mori Seikis," says Ronzello Jr., "It's easy for us to switch jobs over if, for instance, we are in the middle of running an engine head and a customer brings in a bike with an urgent problem that requires components we don't have in stock. We unload the current job, load the new one, call up the program, and the machines run without us having to really touch anything."