New warehouse designs may reduce picking costs 20%
Novel approach to warehouse layout finds diagonal cross aisles are more productive than straight aisles.
By Corinne Kator, Associate Editor -- Modern Materials Handling, 9/1/2006
Why are warehouse cross aisles always straight? That's a good question but few have addressed it.
But that didn't stop engineering professors Russell Meller and Kevin Gue. And when they asked the question, they found an intriguing answer. Cross aisles don't have to be straight. Better yet, an alternate warehouse layout may save up to 20% in picking costs.
The researchers compared a traditional unit-load warehouse with 21 aisles and no cross aisles to two model warehouses with experimental layouts. Computer models showed the professors' optimal cross-aisle layout reduced picking costs by 11.2%. Their second design—a fishbone aisle layout—reduced picking costs by an impressive 20.4%.
While much recent research has focused on efficiently routing workers or batching orders, Gue says, that research has assumed a traditional warehouse layout. Gue and Meller appear to be the first researchers to question this assumption and experiment with nontraditional aisles.
The optimal cross-aisle layout includes two diagonal cross aisles that begin at the same pickup-and-deposit point. Viewed from above, the two cross aisles form a V in the bottom half of the warehouse.
The fishbone layout also incorporates the V-shaped cross aisles, with the V extending across the entire warehouse. The picking aisles below the V are horizontal, while the aisles above the V are vertical.
 Traditional |
 Fishbone |
 Optimal |
These alternative layouts require a facility 3 to 5% larger than the traditional layout, which was designed to minimize the footprint of a warehouse, says Meller. He directs the Center for Engineering Logistics and Distribution at the University of Arkansas.
"But I think that the objectives of warehouse design may be changing," adds Gue, a professor at Auburn University. The cost of space is no longer the only concern, he says. Operational costs are also becoming an important consideration.
Their research, emphasizes Gue, applies only to unit-load warehouses where picking involves moving an entire pallet, such as in grocery warehouses or in reserve storage areas.
Gue and Meller are also working to develop optimal layouts for warehouses that involve case- and each-picking. "And those designs may be totally different," says Meller.
The professors presented their research this summer at a colloquium sponsored by the College-Industry Council on Material Handling Education, part of Material Handling Industry of America (MHIA). It will be published later this year in MHIA's "Progress in Material Handling Research: 2006."
"We are discussing the potential implementation of some of these designs with a major retailer and a distributor," says Gue. The professors have also applied for patents for the design models.
Click here to view the ModernVideo Log featuring Russ Meller and Kevin Gue on higher education.
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