Put-to-light

A light at each destination, such as a shelf slot or a box, tells the worker which one an item goes into, and often how many. The worker scans an item, the right light comes on, the item goes in, and a button confirms it. A batch of picked items is sorted into orders without anyone reading labels or remembering locations; this is called put-to-light.

Put-to-light is the reverse of pick-to-light: the lights show where to put, not where to take from. It is used with batch picking, where many orders are picked together and then split into single orders at a put wall.

A put wall is a wall of slots, one for each order or store, each with a light and a button. Mistakes are rarer because the worker never has to decide which slot an item belongs in.

When it pays off

It pays off for many small orders sorted from a batch, as in e-commerce and store replenishment, where eyes and memory become the limit. It needs enough orders per batch to fill the wall and enough volume to justify the hardware. It pays off less when orders are large, so that one pallet per order is easier, and at low volumes, where a simple table with labelled boxes works.

What the warehouse system does with it

The WMS decides which orders are in a batch and which slot each order gets, and sends that to the put-to-light controller. When the worker scans an item, the controller lights the slot named in the plan, or asks the WMS which one to light; the button press confirms the put and the WMS records it. When an order is complete, the controller can light its slot for packing and the WMS releases the order.

Who makes it

Aioi Systems, ATOP, KBS Industrieelektronik, Lightning Pick, Signature One

In alphabetical order. Not a ranking or a recommendation.