There are many common reasons for coupling failure, such as improper selection, lack of maintenance and poor lubrication. In high-speed or precision applications, improper balancing can also shorten the life of a Falk coupling.
Although Falk couplings are balanced at the factory before they’re shipped, they can slip out of balance from time to time during operation. At high speeds, even the slightest imbalance can result in severe vibration, leading to failure of the coupling as well as the bearings. That’s why checking the balance on your Falk couplings is an important part of regular maintenance for high-speed machinery.
How Imbalances Occur
Although all Falk couplings are designed to be in perfect balance, some slight imbalances do occur in the manufacturing process. Cast metal parts, for example, will always have inherent imbalances. While each of these imbalances may be miniscule on its own, they add up once the Falk coupling is assembled.
That’s why couplings are subjected to a balancing process before they’re sent out the door; this process compensates for the inherent imbalance within a Falk coupling. A professional will check to make sure cylindrical surfaces and bores are concentric with the coupling’s center; hub faces are aligned perpendicularly to the coupling centerline; and bolt circles are accurately positioned.
Fine-Tuning Coupling Balance
Once these initial checks are performed, Falk couplings are then fine-tuned on a balance machine, which can improve the balance by 5-20 percent. Static balance involves rotating the coupling at a consistent speed so the part rotates down to its heaviest side; weights can then be added to correct the imbalance. Dynamic balancing is a more complex method involving mounting the coupling on a turntable to measure wobble and determine where and how much weight should be added.
Assembly Balance
After the Falk coupling components have been balanced, and their high sides marked to allow for optimal assembly, the coupling is put together and inspected for balance a final time. The components are also marked so the coupling may be taken apart and properly reassembled in the future. If any coupling component is replaced, the entire assembly must be rebalanced.
Adjusting your Falk coupling balance can be an intricate and costly process that’s best left to a professional. However, doing so can prevent larger problems down the road.
Posted under Tips and Tricks on Monday, December 19th, 2011