Background
Bins are similar to racks, but hold smaller items, often picked individually and not by the carton. Usually the items in bins are not as heavy as those in racks, so back and shoulder strain can be less. Furthermore, pallets are not used so forward reaches are generally reduced.
However, typically there are still frequent high reaches and low bends. Furthermore, the aisles are often narrow and constrained, which eliminates the use of lift trucks and some types of pick carts. Consequently, order pickers need to use ladders and step stools, which involve additional issues such as carrying and manipulating, as well as climbing. Order pickers often end up carrying items rather than trying to use carts in the constrained aisles. Finally, work areas can be dark because of the narrow aisles and high bins.
Cognitive ergonomics can come into special play in bins:
- Counting the correct number of items in an order
- Identifying the correct items when similarly looking items are stored close together.
Objectives
Ideas and Options
Many of the techniques applied in racks are also applicable for bins.
Additional levels in easy reach
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| Carousel | Additional level |
The smaller size of bins (compared to racks) provides additional options for creating more storage space within easy reach. Two examples are shown above, use of horizontal carousels and adding a shelf above the takewaway conveyor.
With these techniques, it is easier to eliminate highest and lowest levels yet maintain the same number of stock items in the picking area.
Cutouts
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| Cutout |
A common way to reduce high reaches is to simply cut down the side of a box. Note that cutouts do not necessarily eliminate the high reach, rather often just lessen the reach, as the photo above shows.
Carton orientation
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| Vertical: high reach | Horizontal: reduced reach |
In some situations, simply changing the orientation of the carton can put all items within a better reach.
Vertical carousels
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| Vertical bin carousel (enclosed) |
Vertical carousels are increasingly popular for a number of reasons:
- Good use of vertical space
- No need for lift trucks, ladders, or step stools
- Working height always good (no bending, no reaching)
Aprons
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| Order picking aprons | |
Aprons provide a handy way to keep an assortment of pens, clips, and tools needed for picking orders in bins.
“Carhop” tray
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| Before | After: “Carhop” tray | |
A unique alternative to using a cart in narrow bin aisles is to use a “carhop”* tray. The trays are very portable and can be hung from any position in the bins. The mechanism for attachment depends on the design of the bins. The advantages of these trays are:
- The trays can be located immediately adjacent to the bin, for quick and easy picking.
- The surface enables more accurate counting of items, typically by arranging the items in quantities of five, easily visible on the tray.
- The trays eliminate the need to hold items in the hands
*Some fast food restaurants serve food to customers in their cars, using a serving tray that is hung over the top edge of the door window. The system was especially popular in the 1950s.
Light
white paint, white cartons