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MRO Today

Ford parts depot eliminates conveyor maintenance

For the past 12 years Ford Motor Company’s Dallas Parts Distribution Center (PDC) kept preventative maintenance crews busy changing rollers and replacing worn out bearings in an effort to keep operations running smoothly. In fact, the maintenance costs increased to the point that purchasing new rollers was less expensive. Ford’s search for a better solution yielded a supplier of replacement rollers that offered a 10-year service life guarantee. This significantly reduced maintenance costs, and as an added bonus, the new rollers lowered noise levels in the order picking area.

The Dallas PDC recently changed out conventional rollers with Taperhex Gold rollers, supplied by INTERROLL Corp., of Wilmington, N.C. In the past, preventative maintenance crews spent much of their time in the order picking area changing out and repairing rollers on a daily basis. Now, they simply walk through to verify that all is working satisfactorily.

Depot kept busy
The Dallas PDC is one of eight regional facilities that supply replacement parts to Ford dealerships throughout the U.S. The 315,000-square-foot facility inventories more than 58,000 parts for delivery to Texas, Oklahoma, New Mexico, Louisiana, western Mississippi and Arkansas. Other facilities in San Francisco, Kansas City, Atlanta, Detroit, New York, Chicago and Los Angeles are all part of Ford's Direct Order Entry System II (DOES II) network. The DOES program allows the dealer’s parts counter computer to interface with the PDC to verify part number and inventory status.

If the Dallas facility has the ordered part, it will be automatically picked from inventory and shipped to the dealer. If they don't have the part, the computer will search for the nearest PDC that does.

Night owls keep facility active
A normal day in the PDC: Part orders are received during the day and held in the computer. At 10 pm, after the dealers close, the orders are processed and filled. The PDC is set up to pick 30 dealer orders at a time, starting slow, then reaching peak volume between 3 pm and 12:30 am.

The small parts order picking area, that handles parts as small as O-rings and seals up to interior moldings and fascia, is very confined with parts carousels on each side of a powered roller conveyor. As a specific dealer's tote moves down the line, the order picker will be prompted to pick the desired parts.

A bar code/scanning system verifies that each part is put into the correct tote. The small parts area is approximately 160 feet long with a mezzanine to maximize space. In total, 42 parts carousels feed the order pickers.

Once the conveyor is turned on, it runs constantly until all orders are filled, approximately 21 hours per day. It doesn't take long for rollers to begin to wear in this type of operation. Often it starts with a slight squeak or squeal, but eventually as the roller bearings wear the noise gets louder. Within months the roller stops spinning and maintenance needs to pull the roller out for repair.

At first, the fix was simple -- pull out the roller, pop out the bearing, press in a new bearing and reinstall the roller. Obviously, when you are dealing with only one or two rollers, this task is less expensive than buying a new roller. But, eventually the number of failed rollers increased to the point that it was cheaper to buy new rather than replace old.

Quieting factors
INTERROLL's Southwest sales rep., Gil Moore recalls: "Roller service life was a major concern for Ford, but the noise problem also had to be addressed. We have been supplying rollers to industry for over 30 years, and we know the primary cause of roller noise and wear in high-speed, constant running systems is the bearing. Therefore, we use precision bearings in rollers for these applications.

"However, several years ago we also discovered that bearings weren't the only cause. We found that conveyor OEMs typically allow additional clearance in the side frame to facilitate installation of conventional hex shafts. During operation, the shafts will start to rattle in the oversized holes. As a result, shafts and frame holes wear, shortening the life of both the roller and the side frame."

Taperhex: the ultimate solution
The combination of tapered hex shafts and precision bearings have proven to be the ultimate solution. The shaft design is spring-loaded to lock into the side frame, completely eliminating the rattle and subsequent wear.

Taperhex precision bearing conveyor rollers are ideally suited for either new or existing powered conveyor systems. The rollers pop into the conveyor side frame in the same manner as conventional spring-loaded rollers. The self-adjusting tapers wedge tightly in place, regardless of the condition of the mounting holes. The tapered shafts seat tightly in worn holes as well as rounded hex holes preventing further wear.

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