An electronics company had four or five people picking orders from shelving on about 2,000 square feet of floor space. Installing two simple horizontal carousels allowed one or two people to handle the same volume while needing only 700 square feet.
In another application, eight to ten people worked two shifts picking airline parts from an area of about 15,000 square feet. With the installation of an automated storage system and its software, the floor space requirement was reduced to about 8,000 square feet and the payroll to three people.
While the companies in these examples aren’t huge multinationals, they still could use the savings. Eliminating perhaps 1,300 square feet of sorting space might mean putting off a move to larger facilities. Eliminating five or six related salaries might make the difference between loss and profitability.
In both examples, the basic automation tool is the carousel-an automated storage and retrieval system that rotates to deliver the proper part to a particular workstation. Instead of sending people wandering around vast shelving storage areas, carousels send the shelves to the worker, who stands in one place ready to do the next step: load the delivered part to the machine, work on the delivered assembly or pack the part for shipping.
At its simplest, the concept works like this. A vertical carousel in a machine shop is loaded with commonly used tools and small parts. This arrangement uses considerably less floor space than a standard shelving system. When a particular part or tool is required, the operator punches a keypad, the carousel rotates, and the needed item is brought within easy reach. Yes, it takes a little while for the operator to learn which buttons to push. But the first time the operator doesn’t have to waste time looking for a part that has been mislabeled or placed on the wrong shelf makes up for the learning time.
When a plant installs a carousel system, it must revise storage procedures. This usually requires a thorough physical inventory and a rationalization of the process to produce a clean baseline for a fresh start with accurate information and better procedures. The carousel’s accuracy makes it much easier to maintain pristine conditions.
With software-controlled systems, the situation is even better. The computer specifies which picks to make and moves the proper bin to where it’s a simple matter for an operator to make the picks accurately. Then it removes the picked items from the inventory record.
Vertical carousels deliver the correct part or tool to a work quickly and accurately. Horizontal carousels, like vertical types, allow for enormous productivity gains.
Horizontal systems are usually installed in pods, with perhaps two carousels serving each operator. The now-stationary operator follows the instructions on the computer monitor and light trees on the carousel. Because the operator does nothing but pick, the number-of-picks rate rises dramatically.