MODERN Equipment 101: Sortation

A primer for warehouse/DC managers

S
OO
OO
OUTmaterials
R handling
T
By Lorie King Rogers,
Associate Editor

I
N
G Sortation systems, like the tilt-tray one shown here, can
handle the challenging throughput demands in today’s
distribution centers where there is a variety of product
and a need for accurate, high-speed sortation.

36 M A Y 2 0 1 1 / MO D E RN MATE R IALS HAND L ING mmh.com

MMH1105_EquipmentSortation.indd 36 5/11/11 12:07 PM

 From simple pushers to sophisticated crossbelt sorters,

automated sortation systems reduce labor and increase

efficiency and throughput in today’s warehouses and

distribution centers.

t
here are many ways to auto-
matically sort products as they
move through warehouses and
distribution centers. Sortation
solutions range from basic
pushers and diverters that sort fewer than
30 cartons per minute to sophisticated
high-speed sorters that handle as many as
450 items per minute. The right sortation
solution depends on the product you’re
moving and your need for speed. Crossbelt sorters can typically handle product weighing up to 100 pounds
Sortation systems automatically and process up to 200 pieces per minute, regardless of their shape, size and
sort products as they move through surface characteristics.
a facility. They reduce the manual
labor needed to prepare for palletizing, work in conjunction with standard belt Medium-speed sortation
packing, shipping and other indus- or roller conveyor lines. These sorters Medium-speed sortation handles about
trial operations. In addition, sortation typically handle fewer than 30 cartons 30 to 200 items per minute. There are a
systems can increase efficiency and or totes per minute. number of styles of sorters available for
provide more accurate fill rates, lower One example of a slow-speed sorter sorting cartons or totes at these mod-
return rates and operating costs. All of is a deflector arm. In this design, an erate speeds. Among the most popular
these benefits add up to lower prices arm or paddle sits alongside a conveyor are pop-up sorters. These linear sorters
and faster delivery to the consumer. line, opposite a divert point. As a carton usually move products down the line
So, which sortation solution is right approaches, the arm swings out across on belt conveyor. When the product
for you? “Not all sortation technology the conveyor, catching the carton and reaches its divert location, wheels or
is ideal for all types of items,” explains channeling it off at an angle. rollers pop up under the product, lift it
Tim Kraus, product manager for A generous amount of space is needed slightly above the conveyor surface, and
Intelligrated. Among the factors to con- between cartons to avoid traffic jams power it off the conveyor, usually at a
sider, says Kraus, are the types of items behind a deflector arm sorter. These deflec- 30 to 45 degree angle.
to be sorted, the packaging, item diver- tors can be used in a “slug mode” with the A common style of pop-up wheel
sity and predictability. Most sortation arm staying in place to divert a string of car- sorter uses a wide conveyor belt that
systems can handle a variety of product, tons down the same divert point. ends at a divert point and begins again
but aspects such as size, weight, balance Another example of a slow-speed right after the divert point, creating a
or shape of product may rule out certain sorter is a pusher. A pusher is mounted gap in the conveyor. The gap is filled
sortation technologies, adds Kraus. at the side of a conveyor line, directly with several rollers that extend the
Here’s a look at some of the most across from a divert point. When a width of the conveyor. Between those
common types of sortation systems. product reaches the divert point, the rollers are powered, angled wheels that
pusher springs out across the conveyor, sit below the level of the conveyor.
Slow-speed sortation pushing the product off at a right angle. When a carton reaches the gap in
Not every facility needs to move prod- Pushers are faster than deflector the conveyor, one of two things happen:
uct at vision-blurring rates. In many arms because they don’t require as 1. The angled wheels remain in
cases, slow-speed sortation is enough to much space between cartons. But fast place and the carton continues moving
meet the requirements. pushers can pack too much of a punch, forward—across the rollers and onto
Slow-speed sortation systems, the so they are not recommended for car- the next section or conveyor, or
slowest and least expensive sorters, tons with fragile contents. 2. The angled wheels rise up under

mmh.com Modern Mat eria l s Ha ndl ing / M ay 2011 37

MMH1105_EquipmentSortation.indd 37 5/11/11 12:19 PM

 modern Equipment 101: Sortation
A primer for warehouse/DC managers

Sortation equipment manufacturers

tilt sliding
Company Web site Crossbelt Bomb bay Pop-up deflector Pusher
tray shoe
Accu-Sort accusort.com x
Automotion
automotionconveyors.com x x x x
(a Wynright company)
Bastian Material Handling bastiansolutions.com x x x
Beumer beumer.com x x x
Carter Control Systems cartercontrols.com x
Cornerstone Automation
cornerstoneautosys.com x x
Systems
Cinetic Sorting sorting.com x x x x x
Daifuku daifukuamerica.com x x x x x
Dematic dematic.com x x x x x
Eurosort eurosort.com x x
GBI Data & Sorting Systems gbisorters.com x x x
Hytrol Conveyor Company hytrol.com x x x x
Innovative Picking
ipti.net x
Technologies
Intelligrated intelligrated.com x x x x x x
Interroll Automation interroll.com x x x x
Knapp Logistics
knapp.com x x x x
& Automation
Schaefer Systems International ssi-schaefer.us x x x
TGW Systems tgw-group.com x x x
Vanderlande Industries vanderlande.us x x x x x x
This table represents a sample of leading sortation equipment manufacturers.

the product, lifting it slightly off the High-speed sortation Intelligrated’s Kraus.
conveyor. The wheels then rotate, When speed is of the essence, high- There are four common types of
diverting the carton off the line. speed sorters can divert about 150 to high-speed sorters. Tilt-tray, cross-
An alternate style of pop-up sorter 450 items or cartons per minute, or up belt and bomb bay sorters are typi-
uses multiple narrow conveyor belts to 27,000 cartons per hour. Products can cally used to sort individual items to
instead of one wide belt. At each divert be inducted to the sorter manually or workstations such as packing stations
point, angled wheels are positioned in automatically using induction conveyor. or returns processing stations. The
the gaps between narrow belts. These When it comes to induction, the fourth type of high-speed sorter, a slid-
wheels sit below the level of the con- faster you go, the more exact you have ing shoe sorter, usually handles larger
veyor until they’re needed to divert a to be with product placement onto the cartons and totes.
carton. When a product reaches the sorter, explains Kevin Thuet, direc-
divert point, the angled wheels rise up tor of systems development for TGW Item sortation
under the product and divert it. Systems. “If you don’t place that box Tilt tray, crossbelt and bomb bay sorters
Pop-up style sorters work best for exactly—or push that load exactly—it operate under similar principles, and
sorting cartons or other items with firm, will spin and you could have an error each type of sorter has the same foun-
flat bottoms. Other items, like poly bags, and you won’t realize the desired rates.” dation: a looped track with individual
that have inconsistent surfaces are bet- Higher speed means a higher level carriages riding on the track.
ter handled with sliding shoe sorters. of technology and sophistication, but In a tilt tray sorter, each carriage
Sliding shoe sorters are more expensive, speed, without consideration of other holds a wooden or plastic tray. Items
but they are a better choice for fragile factors such as gapping, gentle han- arrive at the sorter and are released one
items and can be run at slower speeds if dling and accuracy, can actually be an at a time onto the trays. An item moves
high throughput isn’t necessary. inefficient use of the technology, says around the track until it reaches its

38 M a y 2 0 1 1 / Mo d e rn Mate r ials Hand l ing mmh.com

MMH1105_EquipmentSortation.indd 38 5/11/11 12:20 PM

 modern Equipment 101: Sortation
A primer for warehouse/DC managers

intended divert location. Its tray then says O’Connor, is for the whole carton
tilts to one side and gravity pulls the to be impacted by the shoes, with a
item off the tray. Items usually slide shoe out front and a shoe behind, some-
onto a chute or onto a takeaway con- times even two out front and behind, to
veyor positioned at the side of the sorter. prevent the product from spinning. The
The tray then rights itself and is ready to idea is as the shoe slides across the con-
accept another item for sorting. veyor, it’s guiding the carton and chang-
A crossbelt sorter works on the same ing its orientation at the same time.
basic principle, except instead of a tray, An alternate design places shoes
each carriage in the systems holds a 2- down the center of the conveyor and
to 3-foot cell of belt conveyor powered pushes cartons in either direction.
by a small motor. When an item reaches A sliding shoe sorter usually sorts
the divert location, the motor moves 200 to 300 cartons per minute, depend-
the conveyor, discharging the item side- on this sorter, the shoes slide across ing on the characteristics of the prod-
ways off the sorter into a chute or onto the slats and push the carton off the uct and on how closely the induction
a takeaway conveyor. side off the sorter, usually at a slight system spaces the cartons.
In a bomb bay sorter, each carriage on angle.
the track holds a flat tray that has a split System controls
down the middle. When an item reaches because they use their own power to A key component of most sortation
its intended location, the two sides of divert products rather than relying on systems is a fixed-position bar code
the tray swing down and apart, dropping gravity. This means the sorter can go scanner. The scanner identifies each
the item into a chute or container posi- faster and the divert locations can be carton or item on the conveyor and
tioned directly below the sorter. placed closer together. sends that information to the sortation
Bomb bay sorters are generally less A tilt tray sorter requires more space system controls. The controls have
expensive than tilt tray or crossbelt between divert locations than a cross- been pre-programmed with the desti-
sorters, but they also have the low- belt sorter, but it also has fewer mov- nation of each product and can acti-
est throughout. And while tilt tray and ing parts, making it less expensive and vate the sortation mechanism when
crossbelt sorters can accommodate easier to maintain. the product arrives at its designated
long items by allowing one item to span divert point.
across two trays or two belts, bomb bay Carton sortation The smaller the item, the more
sorters are limited to small items. And, Sorting cartons at high speeds usually scanners or sensors you need to
the items have to be able to tolerate the requires a sliding shoe sorter. Instead of ensure the item is seen, explains Mark
drop without being damaged. being configured in a loop, a sliding shoe Wolkenfeld, vice president of GBI Data
Additionally, bomb bay sorters have sorter is linear: products enter at the & Sorting Systems. This is also the case
unique benefits when there are space beginning of the line and are diverted with items like polybags because a sen-
constraints in a facility. These sortation before they reach the end of the line. sor can go right through it, he adds.
systems can fit into very narrow spaces The bed of a sliding shoe sorter is Sensors and scanners can go a step
because sort locations are positioned essentially a length of metal slat con- further, says Wolkenfeld. If the product
directly under the sorter track. veyor with a small rubber clock (called being sorted is particularly valuable,
“We’re seeing more and more bomb a shoe) mounted on each slat. In most or if there’s a question about product
bay sorters in use,” says Mike Hahn, designs, the shoes line up along the movement, sensors can even be put in
vice president of Knapp Logistics & side of the conveyor opposite the divert the chutes themselves to confirm that
Automation. “In certain applications locations. The conveyor carries a car- the item was accurately diverted.
they are very good performers. In terms ton along the line, and when the carton As systems have been pushed to
of cost, they provide a good value to reaches its divert location, several shoes continually increase rates, sortation sys-
customers. In terms of space, this type are activated. The shoes slide across the tem suppliers have worked to increase
of equipment is very good because the slats and push the carton off the side off throughput without increasing machine
chutes are underneath not on the side. the sorter, usually at a slight angle. speed, explains Intellgrated’s Kraus.
Bomb bay sorters are very space effi- “The number of shoes activated This makes the machine control system
cient when limited space is available.” depends on the size of the item being much more critical on sliding shoe and
While crossbelt sorters are the most transferred,” says Joe O’Connor, direc- pop-up wheel sorting technologies, and
expensive of these high-speed options, tor of marketing for Automotion, a it reduces wear, energy usage and noise
they also offer the most product control Wynright company. The rule of thumb, while extending equipment life. M

40 M a y 2 0 1 1 / Mo d e rn Mate r ials Hand l ing mmh.com

MMH1105_EquipmentSortation.indd 40 5/11/11 12:22 PM