The Delivery Dilemma Getting Packages On and Off a FedEx Conveyor Network with Magnetic Couplings
Speed and reliability are staples for FedEx. As the world’s largest express transportation company, they deliver to every U.S. address and to more than 220 countries and territories. FedEx has ten Air Express Hubs worldwide handling over 670 aircraft and an average of 3.3 million packages daily.
In each hub a network of conveyors handles the transfer of packages between incoming and departing aircraft as well as between the air and land-based operations. When an aircraft arrives at the hub the package handling team has a set amount of time to unload, service, and reload that aircraft before it departs. For every minute taken over the set limit, the hub is charged $20,000 by the corporate office. Delays of any kind simply are not tolerated.
In the past, FedEx used fluid couplings to drive the conveyors in each hub. Rapid starts and stops required cushioning in the motor/gearbox connection and, at the time of construction, fluid couplings seemed to be the best solution. However, fully loaded conveyors require a lot of torque to start that can cause the fluid coupling to release its transmission fluid. This is dangerous because of the heat of the fluid during operation and the potential to damage packages and their contents. In addition, in the event of a coupling failure, the time taken to replace a fluid coupling was, on average, 30 minutes—too much time and too many variables to avoid costly delays.
A Magnetic Coupling Solution
MagnaDrive Corporation approached FedEx with a proposal to replace the existing fluid couplings with MagnaDrive permanent magnet couplings. Some applications, such as bulk handling conveyors, require a delayed-start capability in order to extend system equipment life.
MagnaDrive’s solution could deliver the benefits of the standard couplings with additional benefits including the ability to delay full torque transfer, provide a cushioned start and stop, and partial disengagement to protect the equipment. The benefits of reduced vibration, reduced maintenance, safety, and increased reliability were compelling enough to convince FedEx to install a MagnaDrive Fixed Gap Coupling (FGC) as a trial unit.
FedEx testing showed that in the unlikely event of a MagnaDrive coupling failure, the replacement time averaged 22 minutes – an eight minute savings compared to the existing fluid couplings.
FedEx tests also revealed that the permanent magnet couplings on conveyor systems reduced vibration, lowered maintenance, and increased system reliability. The results proved real and quantifiable benefits to the FedEx organization.
Based on the success of the first unit, FedEx has not only continued to replace fluid couplings with permanent magnet couplings, they have also worked with management to develop a FedEx specific part number to simplify purchasing of MagnaDrive couplings.
Because of the quick return on investment, FedEx has made the decision to purchase MagnaDrive couplings in spite of the fact that they typically carry a price tag that is greater than the competing fluid couplings.
With the new components, packages now move in and out of the shipping hubs faster and more efficiently helping FedEx maintain their strict operation schedule.
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