MRO Today - Gee whiz maintenance

Gee whiz maintenance
What maintenance engineer or operations manager hasn't dreamed of a production line that didn't need constant babysitting, could do its own maintenance and fix itself
when something went wrong? Look to technology to make
that dream a reality.

by Dan Anderson

Remember HAL, the sentient computer in the classic science fiction movie, "2001, A Space Odyssey"? Aside from his paranoid personality and homicidal tendencies, HAL had capabilities many maintenance and operations managers covet and admire.

HAL was self-monitoring, self-maintaining and self-repairing. What maintenance engineer or operations manager hasn’t dreamed of a production line that didn’t need constant babysitting, could do its own maintenance and fix itself when something went wrong?

As the year 2001 approaches, that technology is no longer entirely the fabric of science-fiction movies. Recent developments in the science of monitoring machinery to predict maintenance, schedule repairs and minimize downtime have created systems with HAL-like capabilities.

Predictive technology: then, now and in the future

Sensing and predicting potential problems in motors, pumps and gearboxes is nothing new. Most maintenance and operations departments are familiar with using vibration analysis, oil sample analysis, infrared sensing and ultrasound monitoring to track equipment performance. Experts in the predictive maintenance field estimate that up to 75 percent of manufacturing companies in the U.S. use some form of predictive maintenance techniques.

Companies accomplish predictive maintenance sensing in a variety of ways. Large companies can often cost-justify owning the sensing equipment and training employees to operate it. Many smaller companies have found outside contractors a cost-effective way to monitor their equipment’s performance.

“In most cases, you can hire someone to profile a piece of equipment for $50 to $100,” says Roy Brandon, with Strategic Asset Management Inc. This firm analyzes equipment, then develops plans to reduce maintenance costs.

“We say the cost of not monitoring is five times the cost of monitoring. That means it’s cost-effective to pay a contractor $100 to monitor any piece of equipment that will cost you $500 in repairs or downtime if it fails.”

To make predictive maintenance technologies cost-effective, the first step is to decide which pieces of production or support equipment are critical to uptime.

“Many people in the predictive maintenance industry cite the ‘20-80 rule,’ which states that only 20 percent of the equipment in a facility is absolutely critical to keep things running,” says Steve Sabin, for Bently Nevada, a pioneer in vibration analysis and other predictive techniques.

“The other 80 percent only slow things down or make life difficult if they fail or develop problems. The goal should be to identify critical equipment and initially spend resources monitoring it instead of trying to monitor everything in the plant.”

As price drops, monitoring increases
As the price of portable predictive sensing equipment drops, the temptation to monitor everything that moves in the plant increases. Workers are often given vibration analyzers or infrared detectors and sent on a mission to check every motor, pump and valve in a plant. The result: a massive data bulge that overwhelms any attempt to monitor and develop a predictive maintenance program.

In leading-edge asset management systems, vibration and temperature sensing equipment constantly monitor critical motors, pumps and related equipment. Instead of spot-checking equipment once a week or once a month for excess vibration, data is collected continuously.

“Spot-checking catches equipment as it is failing,” says Sabin. “Online asset management gives you data that helps you analyze why it is failing. For example, say you have a pump that keeps failing a seal. A spot check might tell you when the seal is failing, but a condition monitoring system, collecting data constantly and analyzed with the proper software, will help you diagnose that the seal is failing because the pump cavitates every time a particular valve opens in the system. It allows maintenance and operations people to move from being reactive to proactive.”

On-site monitoring takes people off site
Brandon cites the wastewater treatment plant in Ottawa, Ontario, as how sensors, computers and sophisticated software can reduce operating costs. Plant managers installed a predictive maintenance and monitoring system that uses a computer to analyze inputs from automated sensors located throughout the system. If excess vibration is detected in a particular pump, the computer shuts down that pump, then uses a modem to page an operating engineer. The engineer dials into the computer and receives a report on the problem.

From his home, movie theater or favorite fishing hole, the engineer can then tell the computer to switch to another pumping system, force the pump back online or make the decision to visit the facility for hands-on repairs.

“They’ve reduced their operating costs by 57 percent,” says Brandon. “They’ve taken predictive maintenance to a higher level by integrating sensing equipment with computer software that does much of the monitoring, data collection and data analysis for them.”

Brandon notes that much of the savings came through reduced labor cost, and warns that management must work with labor to institute such radical changes.

“Any manpower reductions resulting from automation should come from natural attrition and not through layoffs,” he says. “We’ve seen very low success rates from implementing automation if people think they are automating themselves out of a job. You’ll have far greater success if you guarantee them work by using them in a special project to install the system or move them to a new position that makes better use of their experience and capabilities.”

Do it without breaking the budget
Not all operations can justify a predictive maintenance system as sophisticated as Ottawa’s, but most can find ways to use predictive maintenance technologies without sabotaging their budgets.

The cost of hard-wiring maintenance
Monitoring equipment from remote locations does have an appeal: From one location, a computer keeps tabs on critical functions and sounds an alarm if the component falls out of spec. Steve Sabin with Nevada Bently says there are three ways to collect this data with varying price tags.

“If you use a permanent, continuous protection system, expect to spend about $1,000 per channel (component monitored). To hard-wire it and get it on-line, expect to spend about five times that,” Sabin says.

A less expensive approach is portable data collection. Used mainly for vibration data collection, these hand held units can cost from $15,000 to $30,000. “This does not include the labor it takes to gather the data and you lose the continuous monitoring aspect,” Sabin points out.

An alternative method relies on online surveillance. “This is appropriate for less-critical machines,” he says. Here, the predictive maintenance software scans several points on one channel. Installed cost can be as low as $1,500 per point.

Sabin says he truly believes costs will drop as wireless technology comes online.

“There are none on the market now, but several companies are working on them," he says. " The initial cost of system components will be higher, but the installation cost will be minimal compared with the costs of hard-wired systems.”

Expect to see this technology in the next few years.

“Online systems are great and the sensors are reasonably priced,” says Bently Nevada’s Sabin. “It’s the cost of installation, of pulling and installing the wire to the central computer, that may make it hard to justify an online system for all but the most critical assets. Systems using field bus-type wiring rather than point-to-point wiring are driving the price of hard-wired systems down, and the technology that’s coming out of the cellular phone boom is making wireless systems more and more feasible.” (See sidebar at right.)

Sabin also predicts that maintenance and operations departments, traditionally at good-natured odds with each other, will find a common denominator in the latest generation of predictive sensing and analyzing equipment.

“Someone once described an operations department’s job as running equipment until it fails, and a maintenance department’s job as fixing equipment after the operations department fails it,” says Sabin.

He predicts that a new management philosophy will improve relations between those departments.

“Asset management (a.k.a. condition monitoring) will unite operations and maintenance under the goal of maximizing production and minimizing repairs and downtime,” he says.

Being proactive allows workers to schedule repairs on critical equipment before catastrophic failures stop production, damage collateral equipment and send budgets up in high-priced smoke.

It’s like the old oil filter says, “You can pay me now, or you can pay me later,” says Alan Bandes, UE Systems Inc., which makes ultrasonic detection equipment to find leaks, conduct electrical inspections and do mechanical vibration sensing and analysis.

“Maintenance is always cheaper than repair,” says Bandes. “It also has a major effect on profits. If a manufacturer has a four percent decrease in maintenance costs, it affects his net profit as if he had a 15 percent increase in retail sales. Predictive maintenance technologies aren’t as much an expense as they are an investment in maintaining and improving production.”