One Tinker team used to making bold predictions

  • Published
  • By Mike W. Ray
  • Tinker Public Affairs
An axiom attributed to Benjamin Franklin holds that an ounce of prevention is worth a pound of cure. At Tinker Air Force Base, that ounce translates into big bucks.

The 10-member Predictive Maintenance team in the 76th Maintenance Support Squadron identifies and prevents waste through oil sampling analysis, use of infrared equipment to check electrical connections, leak detection with ultrasound, and vibration analysis of electric motors.

According to Allen Logan, a predictive maintenance technician in the 76th MXSS, leaks repaired in argon and compressed air lines that were found by the PdM unit saved an estimated $800,000 in just one year -- and resolved at least one puzzling production problem.

In an Oklahoma City Air Logistics Complex welding shop, several welds performed by veterans who'd been welding for 20 years or more were deemed unsatisfactory. The mystery was solved when an ultrasound device was used on the welding system; a leak found in an argon gas line was pulling in air and moisture that spoiled the welds, said David Robinson, chief of the Equipment Engineering Flight in the 76th MXSS. Patching the leak improved the welds and derailed plans to purchase an auxiliary argon gas storage tank, he said.

Similarly, at least one of the industrial machines at Tinker has a 700-gallon reservoir of highly refined, expensive oil. "Every time we change that oil it costs about $12,000," said Johnny R. Dillon, a certified lubricant specialist in the 76th MXSS. "We try to limit those oil changes from once a year to a 5-to-10-year change."

The PdM team focuses its attention on industrial process/production equipment, Mr. Robinson said. These include mills, lathes, Computer Numerically Controlled machines such as turret punches, air compressors, grinders and furnaces. "We don't have a high number of machine or motor failures at Tinker," he said, and predictive maintenance plays a key role in that, he indicated.

Preventive maintenance is nine times cheaper than a reactive "we'll fix it when it breaks" policy, Mr. Robinson said. The biggest expense associated with an asset is not its purchase, it's the sustainment, he added.

Tinker has approximately 9,800 pieces of industrial plant equipment in its maintenance inventory, scattered among dozens of buildings, he said. About 4,000 of those pieces of equipment receive preventive maintenance on a regular basis, he said, and roughly 10 percent of them have been identified as critical "to safety, to the environment, because it's one-of-a-kind, or it's simply important to the Maintenance Wing's processes," Mr. Robinson said.

A PdM laboratory in Bldg. 3001 performs microscopic analysis of oil samples drawn from many of the industrial machines employed at Tinker. The samples are tested for properties such as viscosity (thickness of the oil); the type of additives in the oil, intended to prevent corrosion, rust or wear; for the presence of dirt, air bubbles or water droplets; and for particulates such as metal fibers.On at least one occasion, Mr. Robinson reported, Tinker received a 55-gallon barrel of oil that, analysis showed, was tainted with dirt when clean oil was poured into a filthy drum.

For reasons such as that, the drums containing oil earmarked for industrial production at Tinker are equipped with filters that can capture particulates as small as 3 microns wide. (To put that in perspective, there are 25,400 microns in one inch.)

Particulates in oil suggest degradation of parts and perhaps metal fatigue, which lead to machine failure. Computer equipment in the oil analysis lab can detect particulates that are as small as 10 microns -- finer than a human hair and invisible to the naked eye, said 76th MXSS Oil Analysis Technician Jason Stroup.

Oil analysis saves money in several ways, Mr. Robinson pointed out: the cost of an oil change includes the labor, the oil itself, and disposal of the used product. "When we can prevent those things from happening unnecessarily, we have significant savings." In addition, he said, oil analysis can prevent equipment failures and extend the life of a machine.

Recently the PdM team analyzed an oil sample from a large air compressor in Bldg. 200 and found particulates, Mr. Robinson recalled. As a result, repairs were made, preventing an equipment breakdown.

"We want to catch problems before the equipment gets to failure mode," he said. "We are checking the health of a machine when we pull an oil sample.""What we're doing is similar to the doctor checking your blood to determine how much cholesterol is in your system," echoed Mr. Dillon.

Computer analysis reveals whether the oil in an industrial machine needs to be drained and replaced; filtered and pumped back into the machine for continued use; or left as is. The oil in some machines has not had to be changed in several years, Mr. Dillon said.
In the not-too-distant past, oil changes were usually based on calendar days or run-time hours. With sampling and computer analysis, Mr. Dillon said, "We don't have to buy as much oil now."

As an illustration, the PdM Oil Lab analyzed samples from 100 pieces of production equipment in May and recorded two "critical finds" that necessitated maintenance investigation because of the presence of particulates in the oil "suggesting worn parts and the potential of machine failure," Mr. Robinson related.

The cost avoidance from analyzing 100 oil samples versus performing 100 unnecessary oil changes included saving 200 hours of labor and buying 1,500 gallons of oil that cost $16 per gallon, on average, Mr. Robinson said.

The PdM team also tests steam and compressed-air systems, electric motors and electric panels.

Ultrasound equipment is used to detect various leaks such as vacuum, steam, compressed gases and compressed air leaks, all of which are "big money losers," PdM Technician Mike West said.

Three PdM employees test electric motors and electric circuits, using infrared equipment and devices such as an accelerometer.

Infrared can reveal anomalies such as loose electric connections. "Infrared can detect heat buildup inside an electrical panel, which indicates a problem," PdM Technician Bobby Ebilane said.

And use of a Dynamic or Static Motor Analyzer to examine an electric motor can reveal whether a bearing is going bad or whether an industrial machine could be operated with a 15-horsepower motor rather than a bigger 30-hp motor. The financial savings from downsizing would include the initial capital investment and the long-term savings on energy consumption, Mr. Ebilane said.

Predicting a potential machine failure before it occurs allows downtime to be scheduled for repairs and minimizes work stoppages, noted Robert Roman, director of the 76th MXSS.

"Our goal is to make industrial processes at Tinker Air Force Base more cost-efficient," Mr. Robinson said.