Pick to Light Warehouse Operations

What is pick-to-light technology?

Pick-to-light technology uses colored lights as signposts directing warehouse workers to the items needed for an order. It’s faster and more efficient than paper lists or electronic devices such as tablets. Even new workers who don’t know their way around the warehouse can easily find and pick each item. 

Next to the terminal's light, a digital display tells employees which item to pick and how many units are needed. After picking the items, the worker presses a button or scans a barcode, and the pick-to-light system automatically updates the inventory in the WMS.

A basic pick-to-light system consists of:

• Lighting terminals, each with at least two differently colored LED lights
• Alphanumeric screens affixed to each terminal
• Buttons at each terminal
• Barcode scanners

How pick-to-light warehouse operations work

In a warehouse using pick-to-light, each storage unit is equipped with a lighting terminal. These units might be totes, shelves, racks, or even an entire container. The warehouse might use pick-to-light technology throughout the entire facility or only in specific sections.

The lighting terminals are mounted on flow racks, workstations, or mobile carts. Each terminal has at least two colored lights. Traditionally, one of the lights is red. A lit red light means nothing is needed from that unit.

Step 1: Lighting the way

The picking process begins by scanning a barcode that sends an order to the pick-to-light software. The system identifies the storage units containing each item in the order. It switches off the red lights on those units and lights up a different colored light.

How many lights a warehouse uses, and what the different colors indicate, vary from one application to the next. You might have different colors to indicate whether the order requires a single item or a case. Or you might have a different colored light for each SKU in the storage unit.

Step 2: Following the trail

The worker picking the order follows the path of the colored lights to find the items they need. Each lighting terminal is equipped with a digital alphanumeric display that tells the worker which item to pick and how many are needed to complete the order.

These flexible displays can also be programmed to provide additional information, such as special instructions or an order number.

Each time the worker pulls an item from the unit, they press a button or scan a barcode to indicate it has been picked. The system automatically updates the inventory in the WMS. The light remains on until the full quantity needed to complete the order has been picked. Then it switches off and the red light turns back on.

Advantages of a pick-to-light warehouse operation

Pick-to-light systems offer several advantages over traditional order picking methods like following lists on paper or a tablet.

• Employees don’t waste time hunting for a specific item’s location in high-density storage areas.
• Pick-to-light has a 99.5% accuracy rate. The lights offer an instant, easy-to-understand cue that alerts workers if they miss an item or pick the wrong quantity.
• The digital system eliminates paper clutter.
• Operators, including temporary or seasonal employees, can be trained in this easy-to-use system in less than an hour.
• Pick-to-light technology can be integrated with your WMS, ERP, or other management systems, updating inventory in real time.

The best environments for a pick-to-light system

Every warehouse operation is unique. While pick-to-light is an excellent investment for many facilities, it takes the right environment to get the full benefit.

• Warehouses that regularly employ seasonal or temporary workers are a natural fit for pick-to-light warehouse operations. The system can be taught in less than an hour, and workers can immediately begin picking orders, even if they haven’t yet learned the facility’s layout.
• Pick-to-light technology performs best in areas with high pick volumes and dense pick faces. A warehouse that carries only a few SKUs is unlikely to get the full value from the system.
• Once installed, reconfiguring the colored lights is not easy. Pick-to-light may not be ideal in warehouses with frequent SKU turnover or those that routinely reslot their inventory.