The case for live storage
September 1st 2010 Item storage will determine how well
product flow can be maintained, says
Edward Hutchison, managing director of
BITO Storage Systems
Order picking is the most labour-intensive and costly
activity in most warehouses - accounting for as much as
55% of the total warehouse operating cost. This alone is
a good reason to choose a mode of storage that gives maximum
efficiency; add the demands of optimum availability of goods,
fast access and on-time delivery within the shortest possible lead
time and it becomes imperative.
Space constraints are another factor. Lean practice may require
consolidating all stock into a single site. Alternatively, it may
require space for picking growing numbers of product lines and
SKUs without acquiring a new building. Either way it means
devising a way of holding the maximum number of products
within the minimum footprint.
Yet this system must also be flexible enough to adapt to
changing circumstances, as stock profiles are increasingly prone
to change due to shorter product line life cycles and more fickle
markets.Many companies will also experience big swings in
picking activity during seasonal peaks.
Will conventional pallet rack-based storage systems support an
order picking system that can meet all of these demands?
Increasingly companies are finding that they can't and are instead
opting for live storage.
For small item picks in particular, the trend is moving away
from traditional static shelving and longspan racking, towards
dynamic carton live storage. This is because carton live provides
a dense storage system that allows faster picking and reduced
manpower, as well as improved space saving and organisation.
Storage density comes from concentrating cartons into flow
lanes.With carton live, goods are fed into the system at the rear
to flow down roller tracks in an inclined lane to be presented at
the front on the pick face. Once a carton at the pick face is empty
it is simply taken away to allow a full carton sitting right behind
it in the lane to flow down on the roller tracks and take its place,
therefore ensuring products are constantly available at the pick
face. Being a First in, First Out (FIFO) system, carton live storage
enables easy control of time critical products ensuring stock is
not sitting around longer than it should be.
Carton live storage system not only maximises the number of
products that can be held on a given footprint, it also gives a
compact pick face. This is because sufficient quantities of fast
moving products can be lined up in the flow lanes rather than,
with conventional racking systems, occupying locations on the
pick face. A greater number of fast moving SKUs can, therefore,
be located within a shorter distance, thus picking zones can be
smaller to reduce picker travel times and increase productivity.
This means carton live is particularly suitable for applications
with a wide range of SKUs and product lines.
For fast moving items in particular, conventional pallet rack
based order picking, with its single, or even double deep, bays
cannot provide enough locations at the pick face to hold
sufficient stock without resorting to multiple replenishment runs
from a bulk store. The alternative would be a very long pick face
to accommodate sufficient numbers of locations for the fast
mover. This of course means increasing travel distances for the
picker. As with replenishment this incurs time and cost.
The live storage principle applies not just with cartons, of
course, but with pallets also and solutions will often combine a
mix of carton and pallet live. Pallets in a live system are ideal for
holding large quantities of small items or extremely fast moving
items. Picking straight from a pallet load not only saves time
decanting these products into cartons, but also a single product
line might need to occupy a whole level of flow lanes.
Where you have combined carton and pallet live systems, the
pallet lanes – for faster moving goods – are located on the
bottom level with the carton lanes above, creating a balanced
work load in each pick zone.
The improvements in working efficiency made possible by a
carton live storage system will more than compensate for higher
initial investment. For example, by providing within a short
distance a greater density of pick locations for products, a saving
on floor space in the region of 15-20 per cent, when compared to
conventional storage, is a reasonable assumption. Products can
be located far more quickly in small pick zones than they could
by traveling round conventional racking. Depending on the
application, travel times for order pickers can be improved by up
to 66 per cent. Furthermore, because the goods move unassisted
into the picking position, order pickers can rely on a constant
availability and are not left
waiting for replenishment. More articles from BITO Storage Systems Ltd: | 
