junction, it could jam. “If you’re going to
do that, you’ve got to understand there’s
a cost associated with it. There’s a risk
involved,” Bonham says.
Product jams occur in automated sys-
tems for a variety of reasons. Common
causes include loose hardware on guard-
rails or pan guards, and open flaps on car-
tons. Sometimes, jams are caused by errors
in data entry, says Scot Filgis, field engi-
neering manager for Dematic. Someone
keys in the wrong dimensions when creat-
ing the item master, and as a result, a too-
big box gets the OK from the dimensioning
system. It gets put into a tote that’s not
quite big enough to handle it. Things might
be fine at first, but when the tote goes up an
incline, the product falls out. This can also
happen when all of the items fit in the tote
or carton but are not arranged well. Some
operators refer to this challenge as “the
Tetris of picking.”
Another no-no: overriding system con-
trols. Conveyor systems typically have sen-
sors that detect when the line is full and
can’t accept any more items. It may look
as if there’s still room on the conveyor and
you might be tempted to try to squeeze in
a few more items, says Kraus. But that’s
a mistake. The system probably will not
have enough time to react and stop send-
ing product down the lane. The result:
a pile-up; potential damage to products
and equipment; and decreased, instead of
increased, productivity.
In other cases, years after a system has
been installed, the item master has simply
been forgotten. Or inexperienced temps
working on the line might route items
incorrectly. In either case, the solution is
to keep employees trained. If they’re on the
job long enough, they’ll probably learn by
experience what’s conveyable and what’s
not. “But you don’t want that to come at
the cost of unexpected downtime,” Kraus
says.
Filgis advises companies to develop what
he calls an “ownership strategy” for any
material handling system. “That strategy
should address everything from audits to
preventive maintenance and the proper
training of technicians to handle break-
downs when they occur,” he says. “Make
sure … you have a plan in place for the
full amount of time it’s going to take
to complete the preventive main-
tenance, based on your operating
schedule,” he says. Scheduling pre-
ventive maintenance by the calen-
dar isn’t ideal, he adds. You may be
over- or under-maintaining your
system. Instead, look at the OEM
recommendations and develop a
schedule based on the equipment’s
hours of use.
As an additional preventive mea-
sure, a “go/no-go” gauge can be
placed at points where people are
loading items onto the system. For
example, that gauge might be a nar-
row opening that makes it impos-
sible to put a too-wide item onto
the conveyor, even if the conveyor
seems wide enough to handle it.
Early warning of a problem can
shorten the amount of downtime
needed for repairs. Some vendors
offer electronic monitoring sys-
tems that send technicians a text or
e-mail alert when there’s a problem,
says Filgis of Dematic. These sys-
tems can often diagnose the prob-
lem so the repair tech knows, say,
that a scanner is down and where
that broken scanner is, so he or she
can bring a replacement to the zone
where it’s needed.
AN OUNCE OF PREVENTION …
So will all these efforts to prevent
problems really save money? Sure,
although it’s difficult to make a
generalization about how much.
“What exactly that cost (of unexpected downtime) is … is very specific to the different types of material handling systems that exist. So,
that looks different for a high-speed
sortation system (than for) a low-speed, simple conveyor system or
a highly automated storage and
retrieval system,” says Kraus. But
whatever the system, an ounce of
prevention is definitely worth a
pound of cure.
