Put to Light


Put-to-Light systems are an effective automated sortation method to break larger quantities of product into individual customer orders, using light devices to direct operators to ‘put’ items. Sometimes the Put-to-Light approach is referred to as ‘scan and sort’. Merchandise that is typically batch picked beforehand is brought to a put station. Operators scan bar codes on individual pieces of merchandise, then lights turn on at any individual customer orders requiring that product.

There is a version of Put-to-Light sometimes called Put-to-Store or Pack-to-Light which is ideal for retail store replenishment order fulfillment where a percentage of full cases are broken down into smaller quantities. In Pack-to-Light applications racks hold one or two shelves or repack cartons. Conveyor in front of the racks allows merchandise to move past the store locations. When the case is scanned, lights turn on for store cartons requiring that product. This allows operators to quickly move down the line and ‘put’ or ‘pack’ items into the correct carton.

Cart Systems
Put-to-Light is frequently combined with computer monitor/LCD Displays, RF, Voice and/or other technologies on carts to enhance the accuracy of batch picking processes. One of these complementary technologies guides operators to the right product locations in a warehouse. Then an RF scan is used to confirm the correct shelf location and/or product is selected, lights on the cart guide necessary ‘puts’ to totes. These automated carts are often referred to as mobile Put-to-Light stations.


Like Pick-to-Light solutions, Put-to-Light systems involve both hardware and software components to drive the sortation process.

Almost all Pick-to-Light hardware products include the following system components:

  • Light Device. This is the primary interface between the put system and the operator. Most light devices offer an LED to locate the product SKU, and a Quantity Display presenting required units. There is usually a Confirmation Button of some type allowing pickers to verify completed tasks. Many suppliers offer their own unique light module products, each with their own form factors, size, colors or other features.
  • Desktop Monitor. Light-directed sorting stations are usually equipped with a nearby LCD monitor to display order information or other details and instructions from the Put software.
  • Installation Materials. Today most leading PTL suppliers offer a bus or duct-based light device mounting system. The new ‘track light’ product design mounts to existing rack or other storage media, reducing installation time and costs. These ‘plug and play’ light displays make users self sufficient for system re-configurations and expansions. Typically other installation materials include the bus or duct, electrical supplies and controllers to facilitate hardware mounting, power and communication.

All Put-to-Light systems utilize software to configure and manage the light-directed order fulfillment process. Today some of the leading Put-to-Light software products are sophisticated order fulfillment execution systems offering a variety of advanced features and options.

Pack-to-Light systems require a more sophisticated software solution and integration with the WMS or primary host software. Put-to-Store processes place greater demand on the host ti drive intelligent merchandise allocations. Especially in cross-docking or flow through environments where full cases of merchandise are consumer to avoid warehousing residual stock.

Often found in batch picking operations, Put-to-Light is often utilized in direct-to-consumer eCommerce or catalog fulfillment as the high number of SKUs and wide variance in SKU velocity preclude deploying a forward pick line or the cost of automating each pick face with Pick-to-Light is prohibitive.

However Put-to-Light has many effective applications that span beyond this including:

  • eCommerce Order Fulfillment
  • Returns Processing
  • Secondary Batch Pick Sortation
  • Secondary Wave Pick Sortation
  • Retail Store Replenishment Order Fulfillment
  • Putaway
  • Kitting
  • Order Consolidation

In the right application light-directed sortation is visual, intuitive and convenient to use. Operators can be trained in hours vs. the days required by other manual or automated approaches. Simplicity is key contributor to a Put to Light system's success. In addition to increased sortation rates and order quality, Put-to-Light systems can potentially respond to daily volume changes with greater agility than more complex methodologies. Successful Pack-to-Light implementation by retailers effectively manages flow-through sortation processes throughout multiple distribution centers in larger supply chain networks.

Some of the primary benefits universal to all Put configurations include:

  • Faster sortation rates, offering an average increase of 40% over paper-based or RF-only based methods.
  • 99.9+% accuracy rates.
  • Shorter Order Cycle Times
  • Optimizes cross-docking or flow-through facilities where some percentage of full cases must be split.
  • Reduced Employee Training Time
  • Improved Customer Service
  • Lower operational costs through reduced labor, errors, rework or chargebacks.
  • Space efficient, adding capacity to facilities with limited space.
  • Cost effective method of automation, and Put systems don’t require a light device at every SKU location as Pick-to-Light systems do.

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