The term “walking papers” generally means “you’re fired.” In the area of picking product, these are the sheets that send pickers along a long aisle of bins looking for a list of products to be pulled for a customer order. Unproductive, tending towards inaccuracies, and short on accountability, paper picking is gradually being replaced in distribution centers and manufacturing plants by pick-to-light (PTL) systems.PTL is a technology featuring lights fixed to picking bins. When a light for that bin is lit, a display tells the picker to pull an item or items out of the bin for an order. The picker then pushes a button, indicating to the system that the pick was made. But before tossing out the order sheets, an operation has to ask itself a couple of questions. The first is typical when bringing on all equipment— is it cost-justifiable?
The Case For PTL
Like all equipment, PTL systems make sense for the right operation. RF terminals, RF carts and voice picking systems handle full cases or slower moving products. Bring on PTL for partial case shipments of one item on up, which are relatively fast moving. to 5,000 SKUs, where 20 percent of the SKUs represents 80 percent of the shipments and where three or more people are picking. In rare cases, PTL can be used for up to 20,000 SKUs.
• Greater accuracy.
• Traceability— Software can answer the question of whether an item is in the queue, if it is being picked, or if it is in shipment.
• Workload planning— Is the picking crew the right size, who is keeping up with the work and what can be done to help them do a better job?
• Replenishment— PTL enables the operation to stay on top of the inventory and respond quickly. PTL is generally married to gravity flow racking, with a push-along conveyor traversing all racks. Bins run along both sides of the conveyor while the gravity flow conveyors supply cases to the bins.
Pick-to-Light aims at increasing efficiency by eliminating errors with fixed bin lights that alert pickers of when to pull items for an order.
Improving On History
As with all technological changeovers, part of the old procedure hangs on with the new way of doing things. In the case of PTL, as with paper, picking was originally based on zones. In paper picking the idea was to avoid a picker inefficiently walking the entire 160 feet or so of conveyors that are present in a typical operation.
In zoneless picking, with the help of hardware and software, pickers can be positioned so everyone is busy all of the time and totes move down the line at an even pace. Planning software aids in minimizing motions in several ways. First is the ability to set-up a ski-hill configuration for the SKUs – the bulk of the picks are clustered more at the beginning of the line and then the picks diminish as the tote moves down the conveyor, requiring people to move the shortest distance.
Track Your Picking
Accountability can still be a problem with zoneless picking. Say, one of the pickers is on not so friendly terms with one of their co-workers and decides to punch several pick face buttons while the other picker is away. The order comes up short and the picker’s accuracy suffers.