Evolve: From preventive to predictive conveyor maintenance

May 12, 2015
Conveyor systems are a foundational – but often underappreciated – component of a plant's architecture.

If you're a plant manager, conveyor maintenance is probably one of the last things you’re thinking about, right? Multimillion-dollar machines get all the attention when it comes to preventive maintenance, tuneups and performance checks—rightly so. Yet it’s your conveyor framework that moves parts from one expensive machine to the next. No matter how great your really expensive equipment is performing, it won’t matter one bit if you have a conveyor out of commission.

While conveyors are one of the foundational pieces of your company’s production infrastructure, they are all too often viewed as a part of the scenery because of their humble nature. It’s not until conveyors are down that they suddenly draw attention.

Failure to maintain conveyor systems is the leading cause for their failure. When a conveyor is down, the entire production line goes down. When this happens, the loss of time, worker productivity and profits because of downtime add up quickly. Factor in costly repair efforts, and you’ll likely be scratching your head wondering why conveyor maintenance wasn’t a higher priority.

Both predictive and preventive maintenance offer cost and efficiency advantages over a run-to-fail approach, but predictive maintenance can be thought of as a more-refined take on preventive maintenance. Preventive maintenance is structured around the life expectancy of various conveyor parts such as belts, bearings, and gear motors. The life expectancy of these parts determines their maintenance and replacement schedule—it's not a bad method, but it's not necessarily the most cost-effective model, either. Replacing parts that are in good condition simply because they’ve outlived their suggested life expectancy doesn’t make good business sense.

Predictive maintenance builds the maintenance schedule around the actual performance of various conveyor components and calls for replacing parts only when they are ready to be replaced. This is where a trained maintenance team that is able to evaluate conveyor systems comes in.

Both predictive and preventive maintenance require that maintenance personnel pay regular attention to conveyors, and both build maintenance schedules around conveyors' needs. However, the predictive model requires that the maintenance staff be better trained in order to effectively employ this model.

Predictive Model Guidelines:
Pay Attention
Conveyors don’t usually get the attention they deserve until there’s a problem. Simply paying attention to them can extend their service life. This has to be a team effort—the employees working with them every day are just as important as the maintenance team. Emphasizing awareness and training staff on how to identify potential problems is vital to the predictive maintenance model.

Warning Signs
Things to look out for:
● Belt or chain - Look for fraying, damage, buildup of debris, or extra slack
● Tracking - If the conveyor belts are off-track, they can quickly become damaged, which then causes damage to other parts
● Bearings – Sometimes you can hear when a bearing is about to fail or feel excessive heat coming from a worn bearing; bearing failure can create the need for major repairs down the line
● Gear Motors - Gearbox noise or excessive heat from either the motor or the gearbox can be a sign of trouble. These warning signs can predict potential drive failure or help to identify other problems such as those mentioned above

Maintenance Checkups
How often a complete conveyor maintenance evaluation is performed depends upon the volume of the facility's production. If the workload is light, conveyors only need to be evaluated one or two times a year. If the workload is heavy, as in a 24/7 shop, then maintenance evaluations need to be conducted at least four to six times a year. Every other month is the safest bet.

Spare Parts
All machines eventually break down. Keeping spare parts for your conveyors is integral to minimizing downtime. Often times, conveyor producers have recommended spare-parts kits specific to each model, whether it be a custom conveyor or not. Keeping at least one or two spare parts for each of the main conveyor components is the safest route.

This should include an emphasis on regular evaluation and maintenance. Ideally, training should involve more than one on-staff employee. A conveyor can go down anytime, and having more than one person on staff with proper conveyor maintenance training ensures that someone will be available to troubleshoot potential problems.

A reputable conveyor manufacturer can provide an audit and offer training for staff to effectively coordinate and implement a predictive maintenance model. In addition, specialists can be deployed for on-site expert evaluations.

Paying closer attention to an often-overlooked (but foundational) part of the production line can yield valuable dividends in maximized uptime and minimized emergency and unplanned maintenance.

Steve Stuff is the director of parts & service / Web applications for Dorner Manufacturing Corp. He can be reached at 800.397.8664 or at [email protected].