Storage system taps unused space

When German automobile manufacturer BMW decided in 1992 to locate its first manufacturing facility outside Germany in Spartanburg, South Carolina, it set the stage for a large investment in the U.S. economy. Since then, the company has invested $1.9 billion in its Spartanburg plant, first in initial construction and then in upgrades and expansions. By June 2002, the plant was producing more than 9,500 vehicles each week.

One model,the X5 sports activity vehicle,spurred a recently completed plant expansion. The first BMW to be launched in the United States, the X5 is billed by BMW as the first true luxury sports activity vehicle (SAV), one that combines the powerful acceleration and exceptional handling of a BMW automobile with advanced traction technologies and all-wheel drive. Its manufacture in the Spartanburg facility also required a plant expansion from 1.2 million sq. ft. to 2.1 million sq. ft.

However, storeroom capacity was not significantly expanded with the addition. "Even with the dramatic increase in production capacity and manufacturing flexibility," says Tony Brannon, BMW's Coordinator of Central Operations Support, "the plant's existing 7,500-sq.-ft. storeroom housing spare parts for manufacturing equipment was not allotted more space."

BMW's solution to its more space dilemma was to move upward rather than outward. As a result, it specified five Remstar Shuttle vertical lift modules (VLMs). "Although drawer cabinets, a pallet stacker and shelving were already nearly full, the room's vertical cube was largely untouched," Brannon says.

Vertical storage and retrieval systems offer improved space utilization. Depending on usable building interior heights, 75 percent or more of a conventional storage system's occupied floor space can be recovered. "BMW had available space,but it wasn't floor space," says Ed Romaine of Remstar International, Inc. "We helped them make use of the space they already had." The five VLMs replaced a length of 6-ft.-high, 35-ft.-long shelving in a corner of the storeroom. Including the 42-in. aisle, they consume only 363 sq. ft. of floor space. BMW calculated that equivalent cabinets would have required 800 sq. ft. of floor space, or twice the area required for the VLMs.

Remstar's Shuttle VLM is a stand-alone, modular system of vertically arranged storage trays, a workstation-type extraction platform and computerized push-button controls for parts retrieval. It stores and retrieves a variety of component containers on specially designed trays and delivers them to an ergonomically positioned workstation. The Shuttle VLM has a fast vertical travel speed of 138 ft. per minute, and an extraction speed of 10.63 in. per second.

One key feature of the Remstar Shuttle VLM is its ability to improve storage efficiency, in addition to capacity. "The [VLM] automatically minimizes tray-to-tray vertical spacing within the stacks each time the tallest item on a tray is removed and the tray is returned to the stack," says Brannon. The auto-optimization feature was the single most important factor in their VLMs, he adds.

VLM operation is easy and responsive to each facility's needs. When a storeroom associate needs a part, the correct tray is lowered automatically by an internal elevator to a waist-high extraction platform, where it is advanced out toward the associate for easy part removal or put-away. VLM tray-to-tray retrieval times range from 30 sec. to 32 sec., and load capacity per tray is 550 lbs. Load balancing is unnecessary because trays are chain-driven from both ends. It accommodates parts as tall as 29.5 in., with minimum tray-to-tray spacing of 4 in.

Items such as circuit breakers, push buttons, small hydraulic and pneumatic valves and cylinders, welding gun components and air wrenches are stored on the trays.

BMW stores larger parts free on the trays, while smaller parts are consolidated in plastic containers. Heavy items with moving parts often are laid on rubber matting to minimize bearing or O-ring deformation from building vibrations. "Before and after each tray extraction, a light curtain sweeps the tray, looking for parts extending beyond its edge and for parts taller than the last height detected and remembered by the VLM for that tray," says Brannon. "The latter information helpfully points out unclosed carton flaps, plastic bags sticking up and other storage irregularities. The curtain also determines the stacking density to be selected when the tray is returned to the stack."

While the addition allowed new production machines to be installed, it did not have to accommodate added storeroom space. Brannon says that not only were building costs and production floor space saved, but the automated and enclosed units protect spare parts from dust and dirt, and provide for easy retrieval and put-away.

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