Operations & Productivity: 10 Ways to Optimize Your System
A free guide to specifying & operating conveyors
10 Ways to Enhance Conveyor Productivity
528 KB PDF, new window
the backbone of effective material handling systems. In this free
downloadable document, you'll discover ways to enhance your conveyor
operation from start to finish. From maintenance tips to problem-solving
answers to testing advice, this quick-reading report is designed for
conveyor users at any point in the life cycle of their operation.
(1) Keep your
ax sharp - maintain your conveyor
There is an
old story about a tree-cutting contest that you should know if you're
running a conveyor operation. The contest was to cut the most wood in a one
day. One lumberjack relentlessly swung his axe, working as fast as he could.
The other stopped to sharpen his ax every hour—and despite the downtime, he
won. To avoid breakdowns and optimize performance, conveyor needs to be
“sharpened,” as well. Since conveyor downtime is painfully expensive, you
should perform scheduled maintenance, check lubrication, and replace
worn-out parts on time.
(2) Know these
fixes to common problems
expensive, and you can often avoid it by knowing the fixes to common issues:
conveyor suddenly shuts down for no apparent reason. Reset the emergency
stop buttons, which are located around the conveyor and are used to shut it
down in case of an emergency. These buttons are often tripped by personnel
or by packages stored too close to the conveyor.
are accumulating in one area of the conveyor. There can be many causes
for this, but in most cases the photo eye is dirty, obstructed or offset.
Save yourself some money and time: check it before you call service.
runs, but the belt doesn't move. Check your conveyor for an overload.
You can eliminate this issue through training and intelligent load
redistribution. If redistribution doesn't fix the problem call service.
Load will not accumulate on one or more zones. Check the air lines for kinks. The
air bags won't work properly if there is insufficient air. Also, check the
air compressor for water since this can cause major problems with the
(3) Get to
know your load
common conveyor specification error is lack of detailed information on load
data and application objectives. Often, load information is neglected and
hardware is selected on an arbitrary basis—a recipe for poor performance and
inflexibility. Examine the load in detail. Make a list of all of the units
that will be handled on the conveyor.
You can find a full guide to load factors here.
- Shape or form. The load must be defined for what it is—a pallet, box, drum,
wire container, engine block, automatic body, or other item.
If the load is a container such as a pallet, box, or tote, know its length,
width, and height. If it is a unit item, the dimensions of the interface
between product and conveyor—such as the load bearing surface—are critical
information. In the case of product on a container, like a pallet of beer
cases, the dimensions of both carrier and load must be known to provide for
factors like overhang clearance. If the load consists of bulk materials,
density and flow rate must be identified.
- Orientation. The position of the load on the conveyor must be
established. A load length may actually become a height when the item is
placed on a conveyor, tow line, or monorail carrier.
- Footprint. The bottom
configuration, or footprint, of a load can have a strong bearing on the
design and cost of a conveyor system.
- The following questions should be
asked about footprints of different types of loads: Pallet – are there block
feet or runners, and in what direction? Are there broken boards, protruding
nail heads, or straps?
- Drum – are there chines? Does the bottom bulge?
- Cartons & boxes – Is the bottom soggy? What about protruding staples? Is the
bottom of the box fan-folded or taped? Does it bulge?
All of these things
could cause the box to act erratically on roller conveyors.
energy-saving controls and devices
very energy efficient compared to the alternatives for moving product
through a facility. Substantial energy and cost savings are possible. How
can you convey more for less energy?
understand your load factors to avoid a variety of issues.
Misunderstanding load factors is perhaps the most common conveyor
specification and maintenance error. We can assist you in tracking down the
necessary information as you specify conveyor loads.
right motor for the job. The motor should run at or near top capacity at
all times. If load weights vary, use two-speed motors and adjustable-speed
drives to enable motors to run near top capacity.
conveyor lubricated. Proper lubrication is a necessity in any energy
efficient system using reducers, chains, and bearings. Besides saving
energy, you'll increase the life of your equipment.
conveyor off when it's not in use. In some operations it may not make
sense to continually switch them on and off, but you can efficiently do this
in many cases. Intelligent controls can help by turning the conveyor off
automatically when it isn't needed.
feeds when possible. You can substitute gravity conveyor for power conveyor in
the right situation, creating both equipment cost reductions and energy
savings. Mixing power and gravity units to conserve energy and reduce costs
is usually possible.
energy savings in mind. Use long, straight runs with fewer drives. If
possible, power the entire system with one drive. Use high-efficiency speed
reducers. Replace worn-out conveyor. Modern conveyors designed more
efficiently, with appropriate controls, deliver significant return-on-
investment based on energy savings alone. Modern conveyors such as E24 DCV
motorized roller slash energy use.
select and integrate vertical and horizontal conveyors
changes are necessary, choosing the right vertical transport device can make
or break system performance. You have to take into account system throughput
requirements, product characteristics, elevation change, number of
infeed/discharge points, manual or automated infeed/discharge, interface
with horizontal transport devices, proximity to workers, safety devices,
environment, and future system requirements. Analysis of the above criteria
will result in an optimum solution. In the unit handling world of a typical
distribution center, examples might include vertical reciprocating conveyors
(VRC's), continuous vertical conveyors, incline belt conveyors, spiral
conveyors, chutes, and scissor lifts.
(6) Test for
installed a new conveyor system, and you're ready to get into production.
Not so fast.
It may be
tempting to turn your system loose, but you'll be money ahead if you allow
time for adequate testing. If you do a cursory checkout, you miss the
opportunity to fine-tune controls and detect hidden mechanical issues.
Conveyor systems can have millions of moving parts designed to work in
concert. Due to that complexity, a new system may need adjustments to
perform. An outline of testing procedures:
Visually inspect the entire system. This is about safety. Are all the guards
in place? Are the pull-stops accessible? Are the safety stickers easy to see
and read? The mechanical and junction boxes should be closed.
testing: Place a small number of items on the conveyor from the various
in-feed points. This small amount allows for a controlled evaluation
process. Look for obvious flaws; make sure all belts function, diverters and
merges work properly. Be sure cartons don't hang up anywhere in the system.
testing: It's time to fully load the system to see how it performs at
full capacity. Examine how high volume works, whether spacing between
cartons is correct, or if any cartons bunch up. Overload areas to check how
the system handles massive throughput and detect where any bottlenecks could
Error recovery: These tests primarily check system controls. Errors are induced to confirm recovery procedures. Examples of errors might include barcode or RFID misreads, or products improperly inducted or removed from the system mid-stream. Additional “operator error” scenarios should be tested. Testers start and stop sections of the system to see how it handles these forces. Also check into “what if ” scenarios to see how the conveyor will react to unplanned events.
what would happen if an operator pushes two buttons at once or pushes one by
mistake and then quickly pushes the correct button. It's important to see as
many possible events as you can, so the system can recover as quickly as
possible from operator errors. For large systems, it's advisable to keep
both mechanical and electrical personnel on site for at least 14 days to
ensure good system operation. Overlap this time with training time if
assures that a system works today—and in the future. A system designed to
handle 80 units a minute might need to convey half that many in its first
year. Don't wait to discover that it chokes at 65; test and find out. A
system operating at a 20% capacity can look flawless, but might bog down at
80%. It's easier to make modifications during the testing than later on
after the system is up and running.
(7) Safety is
a safe way to transport materials through your facility—in fact one of the
safest ways—but they require training, process and vigilance to stay that
way. Here's what you can do: Awareness: Part of the issue, unlike with many
other kinds of industrial machinery, is that workers—and often
managers—don't recognize the potential conveyor hazards. It moves slow
relative to other machinery, and doesn't appear “threatening.” Conveyor
might be seen more like a part of the warehouse than a machine that is
powerful and can be dangerous if used inappropriately. Train new employees
on how to use the conveyor, its on/off switches, emergency stops, and how to
behave around it. And retrain your veteran workers to drive home the point.
Nearly 42% of injuries around conveyors occur while performing maintenance,
lubrication, or other mechanical processes.
conveyor workstations with ergonomics in mind
in combination with workstations is an excellent way to boost productivity
and increase safety. Musculoskeletal disorders can develop when workers
lean, stoop, twist, or reach. These postures are also symptomatic of a less
productive operation. A well-designed conveyor workstation eliminates risks
and optimizes productivity. The two biggest factors are work surface height
and reach distance.
surface height is the height at which hands are normally held to perform
work on conveyed objects. Heavier tasks performed on larger objects require
a lower work surface height than light, higher-precision tasks. Since people
are different heights, one fixed height can't serve for everyone—and you
can't alter the height of the conveyor itself. The thing to do is design the
height appropriate to the load. If you want to vary it, design it for the
taller workers and utilize step platforms for shorter workers. For standing
workers doing belt picking or light assembly, the rule of thumb is about 42
inches. For seated workers, it's 30 inches.
(9) Choose the right belting
A powered conveyor belt is the only component
in contact with both the drive pulley and the
product. Despite this, it’s a frequently overlooked
component. It can greatly enhance conveyor
performance if properly selected and installed, or
cause headaches if it isn’t. There are thousands of conveyor belt styles, materials, thicknesses,
surfaces, and colors to consider. Because belt is
costly and sometimes difficult to install correctly,
getting it right the first time is important. Things
to consider include the kind of load, the need for
increased oil resistance, and applications where
the load & conveyor may make belt tracking
more difficult. Specialized conveying applications
like food handling have entirely different belting
requirements. Others require a belt that assists
the conveyor when items are diverted. Your
application, load and requirements will determine
the right belt type. Know those in detail and
you’re more than halfway to selecting the right
(10) Make conveyor
Today’s conveyors and sortation systems offer
advantages unavailable just a few years ago.
Distribution systems now perform at levels well
beyond their predecessors. One of the more
significant examples occurs within accumulation
systems. Known as Dynamic Zone Allocation,
the system automatically adjusts the conveyor’s
zone length to accommodate the length of
the carton being conveyed. The result is that
product density is increased as required, and
system throughput increased dramatically. More
importantly, if larger cartons are introduced after
the installation, the system is not obsolete. This
technology creates flexibility for today and the
An additional feature of newer technology is “loading zone” functionality—the ability of the system to tell the difference between a load in transport and one that is inserted, and only delay inserted loads is one example. It is all about system performance to meet the growing needs of today’s distribution center.