Even with recent increases in the cost of energy, labor remains the biggest expense for most warehouses. Among all the activities carried out in a warehouse, order picking can be the most labor intensive, especially with manual systems. Inefficiency can lead to additional operational costs, as well as poor service.
To complicate matters, order picking quantities have become smaller while warehouses have become larger. Whatever can be done to improve worker productivity will positively impact an operation's bottom line.
Storage assignment is a key to warehousing productivity improvements, said Dr Kees Jan Roodbergen, assistant professor of logistics and operations at Erasmus University, Netherlands, in his convention focus session on Warehouse Design/Order Picking Optimization. The objective is “to get the right product in the right location so that warehouse workers are moving around the warehouse the minimum amount of time needed to get all the products.”
Generally, warehouses are laid out based on demand of frequency of products, he said, with the faster moving products stored close to the dock doors. However, distinguishing products by frequency for slotting purposes is often difficult to do, much less keep updated.
Another common layout method is what he termed “ABC Storage.” This is where the warehouse is segmented into three sections: A for fast moving items, B for medium movers, and C for slow items.
Additionally efficiencies can be obtained by prioritizing the movement of all products “but this doesn't balance with all the effort it takes to do this and keep it organized,” Roodbergen said.
Using a WMS (warehouse management system) to control the movement and storage of materials within a warehouse can be helpful in designing and controlling an efficient order-picking process, he observed, but no one system is best. “It might pay to hire a programmer to customize a WMS for your particular operation,” he said.
“Warehouse design and order-picking optimization is a very complex matter. The best routing design and system depends on what you do, your warehouse, and your layout.”
Roodbergen directed attendees to visit his website - www.roodbergen.com - where he has several tools for determining efficient order-picking routes.