Vertical carousel

Shelves or bins hang on a loop inside a tall enclosed cabinet, rather like a Ferris wheel standing on its end. When you ask for an item, the loop turns until the right shelf stops at the opening at working height. The person stays in one place while the stock comes to them; this machine is called a vertical carousel.

A vertical lift module keeps its trays in two stacks with a lift between them. A carousel keeps all its shelves on one moving loop, which makes it simpler and usually cheaper, but it brings only one shelf at a time to the opening.

Older carousels turn at a fixed speed and are driven from a keypad. Newer ones are controlled by software that can choose the shortest way round and prepare the next shelf while the picker is still working on the current one.

When it pays off

It suits many small items, a modest budget and a ceiling nobody uses, with one or two people picking at the opening. It pays off most where picking is steady and in sequence, so that the next shelf can be prepared while the current one is worked. It pays off less when several people need the same shelf at once, because only one shelf reaches the opening at a time, and for heavy or oversized goods. A vertical lift module is the usual alternative when speed or tray capacity matters more.

What the warehouse system does with it

As with other pick points, the warehouse system sends the task and the machine reports back. Typically the WMS says which shelf to present, for which article and order, and receives a confirmation when the picker has taken or put away the quantity. Many carousels run on their own controller, so the exchange is often a small interface, and some sites let the carousel run its own sequencing and exchange only stock movements with the WMS.

Who makes it

Electroclass, Ferretto, Hänel, Intertex, Kardex

In alphabetical order. Not a ranking or a recommendation.