picking all the line items requested in that aisle regardless of the customer order that generated the request.
One advantage of zone picking is travel . time savings. Because each a smaller picker's coverage has been reduced from the entire warehouse to order area, the travel time per line item should be reduced from that of strict picking. Again, however, these travel time reductions must be weighed against the costs of sorting and the potential for order filling errors. Additional benefits of zone picking include the order picker's familiarity with the product in his or her zone, reduced interference with other order pickers, and increased accountability for productivity and housekeeping within the zone.
Two methods for establishing order integrity in zone picking systems are progressive assembly and wave picking. In progressive assembly(or pick and pass systems, complete orders are established as their components are passed from zone-to-zone in tote pans or cartons along a conveyor or on a cart. In downstream sortation, order pickers truly work in an item picking mode. In a typical downstream sortation system, an order picker applies a bar code label to each unit picked. Unit-by-unit or in batch, labelled units are placed on a takeaway conveyor for induction into a sortation/accumula- tion system. As before, the productivity gains in order picking must be weighed against the investment in sortation accumulation systems.
Pick Sequencing
Sequence pick location visits to reduce travel time.
In both operator-to-stock and stock-to-operator systems, sequencing pick location visits can dramatically reduce travel time and increase picking pro ductivity. For example, the travel time for a man-aboard ASRS picking tour can be reduced by 50 percent by simply dividing the rack into upper and lower halves and visiting pick locations in the lower half in increasing distance from the front of the rack on the outbound leg, and in decreasing distance in the upper half on the rack during the inbound leg(see Figures 8-36 and 8-37)
Location visits should also be sequenced in walk-and-pick systems. In case picking operations, when an order may occupy one or more pallets, the picking tour should be sequenced to enable the picker to build a stable load and to reduce travel distance. A major distributor of photographic supplies uses an expert system to solve this complex problem.
Paperless Picking
Eliminate paperwork from the order picking activity is one of the major sources of inaccuracies and productivity losses in order picking. Pick-to-light-systems, radio frequency data communication,