It can happen almost imperceptibly. Throughput slows or jams become more frequent, but the change happens so gradually that managers may find themselves scratching their heads over why order fill rates have fallen.
Or it can happen suddenly. A part fails and whole sections of the conveyor system come to a halt, leaving workers idle, maintenance personnel scrambling, and costs escalating.
Although today's conveyor systems are engineered for reliability with uptime rates that flirt with 100 percent, things still can and do go wrong in day-to-day operations. So it behooves managers to keep tabs on conveyor performance. While this might entail some costs, it's money well spent if it prevents a catastrophic shutdown. And this is particularly worth keeping in mind heading into peak shipping season, when managers could be tempted to keep systems running at full speed and ignore warning signs.
We asked several experts in the industry for some tips on preventing problems and keeping conveyors running as efficiently and productively as possible. Here's what they told us:
• Invest in training. Mechanical failures aren't always to blame for conveyor jams and breakdowns. Often, these problems are caused by operators and maintenance personnel who haven't been fully trained in how systems operate, says Diane Blair, director of field operations for Intelligrated. She says taking the time to educate workers on the dos and don'ts of conveyor operation can go a long way toward preventing problems. "Trained operators will see stuff that can cause stress on a system," she says. "Investing in training is well worth the effort and time."
• Don't skimp on maintenance. It can be tempting to let maintenance slide, particularly during peak periods when pressure is greatest to get product out the door. But that could be a serious mistake, warns Boyce Bonham, director of integrator services for Hytrol. He says that skipping routine servicing can cause efficiency and productivity to deteriorate over time.
With today's sophisticated conveyor systems, even the smallest problems, left unattended, can cascade into big issues, Bonham adds. He cites the example of a photo sensor that's not working properly. "Resolving the problem could be as simple as adjusting or replacing the sensor, or just cleaning a reflector," he says. But if left unaddressed, it could cause cartons to be routed incorrectly or trigger frequent carton jams. Jams can then lead to other more serious conditions, like product or conveyor damage.
Blair too stresses the importance of having the equipment checked out on a regular basis. "The biggest thing you can do to ensure you are running efficiently and running all the time is to allow your maintenance team to have access to the equipment," she says.
At the same time, it's also important to recognize when to bring in outside experts. John Clark, director of marketing for TGW Systems, notes that modern conveyor systems, much like modern automobiles, are significantly more complex than models made just a few years back. Those advances may put some maintenance issues outside the expertise of in-house maintenance personnel, he warns. Annual maintenance by the manufacturer or dealer can help identify and prevent problems. "They can take care of things like worn parts and lubrication and help extend the life of the system," he says.
<• Keep it clean. There are lots of reasons to keep a DC as spotless as possible, and those include keeping your conveyor running at peak efficiency. For one thing, dirt and "carton dust"—the residue from the tens of thousands of corrugated cartons that run across conveyors—can gum up the units' mechanical systems.
For another, a clean system and clean floors make it easier to spot problems. "Carton dust can create a maintenance nightmare," Blair says. "You can clean an area, and two days later, it looks like it's never been touched." The problem, she explains, is that the dust could conceal a visual clue like powder on the floor underneath the conveyor—an indicator that belts are rubbing because something is not aligned properly.
• Communicate. It makes sense that those closest to the system would be the first to notice signs of trouble. So be sure to check in with people on the floor periodically. That's particularly important during peak periods when you're trying to push more product out the door, Blair says. "It only takes a few seconds."
Bonham too urges managers to be receptive to feedback from people on the floor. "Stay in touch with the operators," he says. "Many times, they will be the first to pick up on developing problems. If they know you care and will respond, they will be more free with their information. If they share and you don't respond, they may not communicate issues the next time they occur."
• Be prepared. When problems do crop up, swift response is critical. But repairs will be delayed if the rights parts aren't available. To avoid that, Clark suggests working with the supplier to identify the most critical parts—those whose failure can shut down production—and arrange to have them stocked in the DC. Chris Krafft, head of technical services for SSI Schaefer, further recommends storing those parts near where they're likely to be needed, especially in large DCs where conveyors might be located at a considerable distance from a centralized stock location.
Krafft also encourages managers to establish some sort of mission control for maintenance that provides a centralized view of performance problems detected by the system's diagnostics and automatically dispatches maintenance personnel to the relevant site. That sort of system can reduce response time, he says.
• Consider upgrading your components. Conveyor technology has undergone rapid advances in recent years, with the result that newer units operate much more efficiently than those made just a decade ago. Taking advantage of these technological gains does not necessarily require major capital investments, however. Often, companies can retrofit existing systems with some of the newer components.
An example cited by most of the experts interviewed for this story would be installing photo-eye sensors that shut down sections of the conveyor when not in use. That's now fairly standard on new systems, but it's a technology that some older systems could easily adopt. The benefits include quieter operation and reduced energy consumption. On top of that, keeping motors and belts from running constantly extends their useful life, adds Krafft.
Mike Bozym, manufacturing engineering manager for Dematic, also notes that newer energy-efficient motors, mandatory in new systems, can be installed in many existing systems to cut energy use. Krafft echoes that advice but adds a caveat: Compared with older motors, the newer motors have a steeper energy spike when they start, which can trip breakers designed for the lower loads. He says he's seen operations that keep the new motors running in order to avoid that problem—effectively canceling out any energy savings.
While end users may be able to address this by modifying the geometry of their electrical panels, Krafft says it's something they should be aware of from the start. "If you are looking into more energy-efficient motors, check the start amp requirement," he urges. "Don't get caught with a solution that forces you to keep the motors running all the time."
Ensuring consistent, efficient performance, then, comes down to paying attention to the little things—to slight dips in throughput, to unexpected jams, to dust or oil where they shouldn't be, to workers on the DC floor who notice something amiss. Respond to those warnings—and stay on top of maintenance—and your conveyors should run without issue right through the peak season.
Conveyors generally don't break down without some warning signs, whether it's something visible on the belts and rollers or a change detected by electronic monitoring devices. Since a quick response can head off more serious problems down the road, conveyor experts recommend keeping close tabs on the system's vital signs.
How do you go about monitoring your conveyor's health? One of the primary ways is to keep a close eye on uptime and throughput, the experts say. "Throughput is one of the surest measures of conveyor performance," says John Clark, director of marketing for TGW Systems. "It's also one of the easiest to monitor," he adds. Throughput problems can have multiple causes, including scanning issues that may have nothing to do with the conveyor itself. But any drop in performance is a warning sign worth heeding, he says.
Boyce Bonham, director of integrator services for Hytrol, says for his money, one of the best ways to track a system's performance is through operational reports. "If you have them, use them," he says. "If you are not getting them, get them. What is your throughput throughout the day? What read rate are you getting through your scanners? These reports can ... give you some clues on when equipment may need attention."
Diane Blair, director of field operations for Intelligrated, urges users to take advantage of the diagnostic tools built into most modern conveyor systems. She tells her customers to watch for indicators like an increase in shifts of freight to divert lanes, an increase in time-outs, or a growing number of side-by-sides (cartons positioned two abreast rather than single file).
Blair also recommends keeping an eye on motor temperature, since changes can signal trouble down the road. "If you detect a problem, you can then make a decision whether you want to proactively replace the motor," she says. "You know it's going to [need replacement] at some time."
Mike Bozym, manufacturing engineering manager for Dematic, advises users to watch out for any fluctuations in amp draw. "If you're drawing four amps, then you start drawing five or six, you know you have some kind of wear," he says.
For all the recent advances in conveyor diagnostics, one of the most effective techniques—and one of the easiest to implement—remains the old-fashioned walk-around. "Take time every day to walk the system and pay attention to what's going on," Bonham urges. "Often, people walk all around a conveyor system and never look to see what's going on. Are cartons flowing the way they should? Are you experiencing jams regularly in a particular area? Don't accept that as a norm. Find the root problem and fix it."
In addition to observing carton flow, managers should take a few minutes to examine the belts, Bonham adds. "Are they tracking properly? Are they in good condition?"
Bonham offers one more piece of advice to managers regarding the daily inspection: "Listen as you walk," he says. "Many times, problems start with unusual noises."