Article from LUBES'N'GREASES
By Lisa Tocci
Pratt & Whitney, the $13 billion subsidiary of United Technologies Corp., manufactures and assemblies jet engines for commercial and military aircraft at its East Hartford, Conn., facility. Sister company Hamilton Sundstrand also makes aircraft components at plants in Connecticut. But while Hamilton Sundstrand could point to years of successful metalworking fluid management, for a long time Pratt & Whitney's experience just stank - literally.
In 2005, for example, managers at East Hartford's L Building heard 140 operator compliants of bad odors related to the facility's metalworking fluid. These grievances usually were handled by immediately dumping the coolant and refilling the machine sumps with fresh fluid. L Building could open a drum of soluble oil concentrate, make it up for service - and throw it away only two weeks later. That year it churned through 140 drums of coolant concentrate.
L Building's CAN Module Center makes combustors, augmenters and nozzles for jet engines, including the F119 engine for the U.S. Air Force F22 Raptor, and the F135 engine that propels the F35 Joint Strike Fighter. Four years ago, with 75 machine tools to keep running, L Building was dumping bad coolant so frequently that it had three full-time employees whose principal job was to pump out and refill the machine tool reservoirs, recalled Milton Hoff, vice president of strategic technology development at Master Chemical Corp. in Perrysburg, Ohio. Speaking in May to the annual meeting of the Society of Tribologists & Lubrication Engineers, Hoff described how a comprehensive and disciplined approach to its coolants made L Building a model that other Pratt & Whitney plants now hope to copy.
Before its turnaround, Hoff said, "you could walk in the door at L Building, and the odor was so bad it would make you want to walk right out again." And with all the flushing, coolant waste volumes were enormous: in 2005, the facility had to dispose of 900,000 pounds at a cost of 5 cents a pound.
"That's when Pratt & Whitney realized that they needed to maintain the fluid process the same way they maintain their manufacturing process." Hoff said.
This was not the first attempt to manage fluid at Pratt & Whitney, he added, and past failures had left operators skeptical, after being let down so many times. Managers and workers alike felt bitten by the piecemeal "programs du joir" that promised more than they delivered, said Hoff. This time would be different, however, because it would be an all-out effort led by an agent of change: David Antinore, Pratt & Whitney's specialist, indirect materials and processes was given the mandate to bring the fluid under control.
Antinore began by establishing ambitious goals: Cut waste by 98 percent, reduce fluid consumption, put an end to the odors - and keep going even if immediate success did not come. From a glance at Hamilton Sundstrand, which had gone 14 years without throwing coolant away, it was obvious that L Building would have to be persistent in its efforts and keep a long-term view.
Benchmarking against Hamilton Sundstrand also showed where specific improvements could be made. For example, in its program Hamilton Sundstrand had gone from 1 million pounds of liquid waste a year to just 30,000 pounds, an astonishing 97 percent reduction. It had reduced the labor needed to maintain its coolants from six workers to just three. And it was saving more than $300,000 a year in new coolant purchases.
Antinore proceeded to build a team of experts that included Haas TMC, the plant's chemical management service provider, and fluid specialists Master Chemical Corp., which had participated in Hamilton Sundstrand's success. Also aboard were experts from MSC Filtration Technologies, to work on fluid purity, Under Antinore, the team tore into every factor that might improve its results.
• The fluid. The company had been using a soluble oil cutting fluid. Now it switched to a Master Chemical Trimbrand soluble oil emulsion designed for heavy-duty machining and creep-feed grinding of aircraft alloys. Importantly, the chlorine-free and low-foaming fluid met Pratt & Whitney's stringent PMC 9390 specification for use on all metals, and was recyclable with conventional equipment
• Recycling equipment. MSC Filtration of Enfield, Conn., designed and supplied a new filtration system to keep the coolant free of degrading contaminants. MSC's Barry LaFoe, who co-authored the STLE paper with Hoff, recommended coalescing filters which were arrayed in a series of increasingly fine settings, down to 5 or 10 micron particle size.
• Sump modifications. L Building's machine systems themselves were one of the obstacles to maintaining the fluid. They had large, shallow sumps which were hard to clean. "Their shallowness also made it difficult to draw out tramp oil," Hoff said, "because you couldn't use simple belt skimmers." There was a lot of tramp oil, especially from leaky older machines that sent a fair amount of hydraulic fluid into the coolant sumps. Pratt invested in rebuilding many of the machine reservoirs with an eye to easier maintenance, and added top-off stations where needed.
• Training of machine operators, managers and coolant technicians. These sessions covered fluid chemistries, testing techniques, the recycling equipment and how the systems worked together. "You have to train, train, train," Hoff remarked. "For our first training session, only three people showed up, but success breeds success, and more participants joined in a good results began to come in." Soon, the classes were jammed.
• Monitoring of coolant condition and concentration, and scheduled sump recycling. Initially L Building worked towards reaching a 28-day cycle for its coolant, then built it up from there. The monitoring goal was to keep the fluid as close to its original parameters as possible.
Even with this multipronged attack, not every improvement was immediate or sustained. "Things happen." Hoff said realistically. When seasoned workers left or were out on vacation, the fluid concentration levels might be neglected, so they went out of control and problems reappeared. But such setbacks weren't allowed to derail the effort. "In those cases, we got back to training the operators, showing why they're hurting themselves. You have to reinforce, set goals - and don't panic when something goes wrong."
Today, L Building at Pratt & Whitney has not quite reached the goals set in 2005, but it has greatly narrowed the gap. From 900,000 pounds of waste coolant in 2005, it sent out just 100,000 pounds in 2008. it expects to see a further reduction to just 40,000 pounds this year. After hearing 140 complaints about odor four years ago, it now has zero. "Operations are very pleased, there's basically no odor now." stated Hoff.
The crew count in coolant management also reflects the improvement. Although it now has 90 machines to manage, L Building needs only one person (instead of three) to maintain the coolant by himself.
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