The Skinny on Put-to-light

Dec 20, 2006 10:13 PM  By

Put to light is a way to direct activities such as single item distribution and order consolidation via light directed devices. Put to light uses the same hardware as a pick-to- light system, but it reverses the process.

One common application for put to light is to distribute large quantities of a single fast moving, one-time, or seasonal SKU to many different stores. Last month we looked at a sorter application that performed the same function. Put-to-light systems are often mounted on shelving or flow rack, and then individual store order boxes are placed into position over the lights. With put to light, the operator scans the inbound vendor carton containing exactly one SKU. As soon as he scans the inbound vendor box, lights under the store boxes light up and tell how many units to put into each store container. If a SKU tends to get distributed to most of the stores, this method of distribution results in a high put density (lots of put opportunities with very little walking), and an efficient transfer of materials.

Another type of put-to-light system is a put to light cart. When the products you are selecting are not common to many orders, a put-to-light cart is a better alternative to a rack mounted put system. Such a system can be used even when no single SKU is common to more than one order. A put-to-light cart is loaded with multiple customer orders on the cart shelves. A light display is placed across each shelf, under each unique customer order. The picks for all the orders are then identified and sorted in walk sequence within the area where product is stored. An RF display or centrally mounted light display on the cart directs the picker to the pick location in sequence, one location at a time. The operator makes the pick, and then turns to the cart to see what customer orders(s) should receive the item. The light lights up directly under the order to show the proper placement and unit quantity. If an item is common to two or more orders, one pick from a storage location can be distributed to two or more orders on the cart, via the quantity display that is shown under each order.

One final application for put to light is to consolidate order components, which may come from several different zones in the distribution center, into a single order carton or container prior to shipping. An example where this might happen is when a conveyor system is used. In this application, the conveyor will transport partial order components in totes from two or more different areas of the facility to a central consolidation area. The operator at the consolidation area scans the tote, and a light will light up showing him the shelf where he should place the order components. He may deposit the materials into a master order carton, or he may queue up several totes into a particular storage location (rack, shelving, or flow rack lane). When all of the order components have been received, the system will direct the operator to pull and consolidate the materials for shipping. The lights direct the placement of the first consolidation requirement, and any subsequent requirements. Lights also tell the operator when to close out the order and ship it.

Sam Flanders is president of Durham, NH-based operations consultancy Warehouse Management Consultants.