A common task needing automation is Multi-Line Palletizing, sometimes referred to as built-to-order palletizing or order-building palletizing.
Fundamentally, these types of systems allow a distributor to build final pallet orders to ship directly to the end user by way of pulling from multiple lines of same type product pallets. The robot is told what quantities of each type of product should be used to build a final complete pallet for shipping. It then automatically builds that pallet using available product from a variety of other source pallets inside the reach of the work cell. When one of those pallets runs out of product, a new pallet of that product type is delivered to an empty location where the robot can continue to pull items from it.
Gantry robots are one of the best solutions for multi-line palletizing situations due to the virtually unlimited length of pallets that could be placed in the envelope to pull from. In contrast, an articulated arm’s limited reach can generally only build extremely limited quantities of build-to-order pallets unless placed on a rail. In that case, the articulated arm has effectively just become the end-of-arm tool of a gantry robot.