Solving Old Problems
Preventive maintenance system not working? High-maintenance components wearing you down? Training needed on critical bearings? Machine wear taking its toll? Need to do better system monitoring? Require an easier way to monitor equipment health?...
Preventive maintenance system not working? High-maintenance components wearing you down? Training needed on critical bearings? Machine wear taking its toll? Need to do better system monitoring? Require an easier way to monitor equipment health? Well, you’re not alone. These are the same problems experienced by companies profiled in previous case studies published in Machinery & Equipment MRO. So we sent writer Carroll McCormick back to talk to some of those same companies again and learn how they have dealt with their problems. Each has found innovative and effective solutions.
When Machinery & Equipment MRO profiled Lasalle, Quebec-based shingle manufacturer Building Products of Canada Corp., the maintenance department was well into a program to regain control of maintenance from a preventive maintenance system that was not working (Bringing Maintenance Back to Reality, November 2009). Additional training has been part of the cure.
In the past three years, the maintenance team, which includes mechanics, pipefitters, welders and machinists, has received training on bearings, power transmissions (belt pulleys, sprockets, chains and couplings) and laser alignment for couplings.
Denis Lanciault, vice-president of operations, BP Canada, focuses in on the bearing training, which the entire 30-member team has received from Montreal-based Proaxion. “They received training adapted for critical bearings we have on our equipment. They received information about different kinds of bearings we have, learned how to assemble them on the shafts, learned how to analyze and measure wear, and how to choose adequate bearings for different applications.”
Nimble skills with bearings are awfully handy in this plant, as aggressive conditions such as sand, asphalt, gravel, limestone, hot and cold water and tar can kill them in less than a month.
Staff received training on site in groups of seven or eight. It was a refresher course for some and completely new information for others. They spent about eight hours working with bearings on workbenches, and then they went directly to machines in the production line to finish their training.
“Our guys are becoming specialized in replacing and maintaining some of the bearings we are using for special applications. They are better able now to analyze the causes of bearing wear, like contamination by water or dust, overheating, overloading or just normal wear,” Lanciault says.
The maintenance shop was already well-outfitted for most bearing interventions. The company only had to purchase filler gauges for gapping bearings before and during installation. As for the program’s benefits, Lanciault explains, “It increases the lifetime of bearings because they are well-installed and tightened, it reduces downtime due to unplanned breaks and leaves us more time during planned shutdowns. Proaxion is also analyzing and monitoring critical bearings for us. Then they send us a summary of their data analyses that guides us for preventive bearing replacements.”
After 14 months and 175,000 tonnes of garbage, it is time to change out the shredder at the Otter Lake Solid Waste Management Facility just outside of Halifax, NS (High-Motivation Maintenance, September 2010). With the big machine, designed to reduce garbage to pieces five centimetres in diameter or less, all that tonnage has taken its toll. The sizes of the pieces have been creeping up to 15 centimetres in diameter, a sure sign that the shredder is ready for a rebuild.
Otter Lake processes between 550 and 600 tonnes of garbage daily. After removing as much recyclable material as possible, the rest goes through the 14-tonne shredder, to the Waste Stabilization Facility (WSF) for partial decomposition, and then onward to landfill cells.
Otter Lake has two shredders. In April 2012, the one that has been munching garbage non-stop for over a year will be removed using a 90-tonne crane and a rebuilt spare put in its place – a four to six-hour operation. “I’ve been doing this for 14 years. We have it pretty much down to a science now,” explains Terry Barkhouse, head of maintenance for Mirror Nova Scotia, Bedford, NS. The private company runs the facility for its owner, the Halifax Regional Municipality.
As the shredder wears and the shredded pieces get bigger, they interfere with the functioning of the agitator units in the WSF. Too, Barkhouse notes, “As the teeth get worn, the jamming increases.” This is a bad thing, as the system has to be shut down and the offending object, say a lawnmower blade, cut out with welding torches.
The worn unit will be moved to the shop, where maintenance will tear it down, discard the old shredder disks and install a new cutter stack package from the Oregon, US-based manufacturer, SSI Shredding Systems Inc. The package, which includes new disks, seals, bearings and spacers, costs US$50,000.
“We rebuild it in our spare time. We usually have it done in three to four weeks and it’s tarped, ready to go. We don’t like to leave it for too long,” Barkhouse says.
In June 2011, Montreal-based Cofely Services, began installing monitoring devices on the 10 linear motors on the tilt tray system, part of the baggage handling system (BHS) at the Montreal-Trudeau International Airport that serves domestic and international traffic (Strength in Numbers, September 2009).
The tilt tray system is a racetrack-shaped, 230-metre long conveyor that consists of 212 wooden trays. As bags journey through the BHS, conveyors push them onto the trays, which circle endlessly like sushi boats in a high-flying restaurant. When a tray and its bag pass above the chute associated with the right baggage wagon and the right airplane, the tray tips the bag onto the chute. The tilt tray system is the highest-maintenance part of the BHS, requiring 160 hours a month of preventive maintenance.
The new motor monitoring system will track electric current consumption to create a baseline of a healthy motor. It will then compare this to a graphical trend of each motor as it approaches the end of its useful life. With the proper trending and analysis, the maintenance team will be able to tell when a motor is about to fail.
The motors are all driven by a common frequency inverter. It can be difficult to detect a motor failure, since only seven of the 10 motors are required to operate the tilt tray system. Yet a failed motor can eventually affect the frequency inverter and shut down the system. “We want to eliminate the perturbation of [the BHS] caused by a tilt tray failure and we also want to protect the element representing the single point of failure, which is the frequency inverter,” explains Pierre Loyer, director of airport services for Cofley Services.
“We are integrating the data in our centralized database for our reliability analyst to interpret. Eventually, our computerized maintenance management system, Maximo, will be able to generate automatic work orders and produce an overall equipment efficiency dashboard,” Loyer adds.
The tilt tray motor project is part of a larger picture: the ongoing adoption of the 5S concept, including systematic and condition-based intervention, which Cofley began implementing in September 2011. As more system monitoring equipment is installed, other goals are to extend the expected life of specific parts or equipment, benchmark equipment to identify improvement project opportunities and further train the maintenance personnel.
Since November 2011, Canadian National Railway Co. has been using three different systems, each on a different set of some of its locomotives, to remotely monitor their health (Workin’ on the Railroad, April 2005). The goal is to collect data that will indentify trends that can be used to prevent failures and help CN rewrite its periodic maintenance tasks based on actual locomotive needs.
The first system is EMD Intellitrain, made by Electro-Motive Diesel Inc., LaGrange, IL. Intellitrain sends a data pack, which includes five seconds of data prior to a fault becoming active, to a central location whenever a locomotive generates a fault. EMD analyzes the fault and generates an e-mail with a description of the fault and troubleshooting procedures to identify the reason for the fault.
Intellitrain also collects data from the locomotive every hour when it is performing under certain defined conditions. EMD can then send out proactive e-mails with maintenance instructions that can prevent a possible failure. The messages include trends like crankcase pressure building up, coolant pressure getting low or cooling fans not performing as intended.
The second system, GE Expert-On-Alert, by GE Transportation, Erie, PA, transmits real-time incident data to a central location, where remote monitoring diagnostics specialists review the data and issue repair recommendations.
There are three codes, depending on the severity of the incident: Red indicates that an immediate action is to be taken to prevent the locomotive from becoming disabled on the main line. Yellow requires that a plan be put in place to insure that either a temporary correction is taken or plans are put in place to continue working with the locomotive at a repair facility. White indicates a recommendation to correct something that is not going to have an impact on the performance of the locomotive, but that needs to be done the next time it is in the shop for repairs or maintenance.
The third system is Wi-Tronix from Wi-Tronix LLC, Bolingbrook, IL. When a fault is logged, Wi-Tronix sends data and a description of the fault to a website where CN personnel can review the data pack and provide additional information to help identify the reason for the fault. The goal is to identify trends so CN can take corrective action when the locomotives are in the shop for maintenance.
CN has a weekly scorecard it uses to evaluate the benefits of all three systems. It is studying the accuracy of the troubleshooting instructions and how well they work to prevent main line failures.
All four companies that were revisited to update their original stories had made progress with their maintenance issues, using technology, training, new systems or improved planning, reflecting the fact that preventive maintenance and problem-solving are continuous processes in most forward-thinking industrial facilities.
Montreal-based Carroll McCormick is the senior contributing editor for Machinery & Equipment MRO.
To view the full layout of this article with images, as it originally appeared, see page 11 of the April 2012 issue. The digital edition of this issue can be found here: