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Tunable Tooling System (TTS)

Tunable Tooling System (TTS)

Overview

When machining with extended length setups, undesirable regenerative vibrationsThe problem with these solutions is that they do not allow high metal removal rates
(chatter) can arise, causing poor surface finish, dimensional control issues, and toolto be maintained. To uphold high rates, the dynamic stiffness of the system must be
breakage. To avoid chatter, machine operators are generally forced to reduce cuttingincreased. Dynamic stiffness is proportional to the product of static stiffness and
parameters, which decreases metal removal rates and diminishes productivity.damping ratio. Static stiffness can be increased through using shorter setups or
larger toolholder diameters. Materials with a higher modulus of elasticity can also
Cutting force fluctuates when chip thickness varies. This is caused by waves left onincrease static stiffness.
the workpiece from the previous pass. These waves may create chatter when the
cutting tool and workpiece interact. Continued chatter can further produce variationThe WIDIA™ Tunable Tooling System (TTS) provides a means for maximizing the
in cutting force, leading to more vibration. If not addressed, the amplitude ofdynamic stiffness of boring bars and milling adapters by suppressing vibrations with
vibration may eventually reach levels that cause the tool to bounce out of thea passive dynamic absorber. TTS is designed with an internal mass that vibrates
workpiece or even result in catastrophic failure.close to the natural frequency of the most dominant vibration mode in
the system. The motion of the internal mass will dissipate energy and prevent
This problem can be approached in many different ways. Chatter can be avoided bychatter. The overall result depends on a machine’s dynamic characteristics*
drastically reducing cutting speeds to increase process damping (friction betweenand the rigidity of the connection between tool and machine tool. Manufacturing
flank face and workpiece), which dissipates energy to reduce vibrations. Anothertolerances, preload, and wear may change the dynamic response of a machine and
approach utilizes milling cutters that have inserts with differential spacing. Thisadversely affect overall results.

minimizes the regenerative effect by creating a disturbance on the wave pattern left on the workpiece. However, this approach provides limited success as chip loads are no longer evenly distributed over the cutting edges and may require the feed *Machines from same builder and model are not dynamically identical.

rate to be restricted. Also, because the spacing is not even, the surface quality could be negatively affected.

While passive dampening improves the dynamic stiffness of an extended reach tool, the damping mechanism will not perform the same with every machine. Not only does the natural frequency of the tool affect its dynamic stiffness, frequencies inherent to the machine do as well. Because machine tools have their own dynamic signature, a tool that is tuned on one machine may not be tuned on another. Unlike other products on the market that are pretuned, WIDIA tunable boring bars and milling adapters are tunable. They allow users to adjust the passive damper, optimally tuning the tool for a specific machine or setup. This enables extended reach tooling to be retuned to match a machine’s dynamic signature, even as it changes over time. A key benefit of WIDIA’s tunable boring bars and milling adapters is that they can be optimally tuned for any given setup. While WIDIA standard tunable products come pretuned from the factory, it may be beneficial to further optimize them once installed.

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