August 2008 Edition

COOLANTS

New Coolant was the Right Prescription for a Medical Manufacturer’s Sump Woes

Biostable metalworking fluid improved a shop’s environmental outcome

Coolant deterioration was leaving a sour taste in the mouths of the managers of a medical manufacturer, as well as sour coolant in the storage tanks. The company went looking for a different fluid prescription.

Manufacturers of medical device components adhere to strict guidelines mandated by the U.S. Food and Drug Administration, the International Standards Organization, and other organizations. Often, these standards limit the actions plant managers can take to change manufacturing procedures if operations are not running efficiently.

When Tier ONE LLC, Newtown, CT, began experiencing coolant issues leading to increased off-site disposal, the company had to find a suitable method for decreasing coolant-related costs.

The company machines and assembles parts for clinical analyzers, centrifuges, stomach suturing devices, ultrasonic surgical devices, and other medical equipment parts using stainless steel, titanium, and aluminum. To machine these materials cost-effectively, Tier ONE’s tools need to be fine-tuned to promote long life.

Tier ONE plant managers noticed the coolant they were using during machining was souring in the coolant tanks, increasing costly waste removal. After researching options that would meet medical manufacturing standards, the company found a coolant that saved them $21,000 annually in waste removal costs.

Coolant Quandaries

When Tier ONE’s tanks began developing build-up, the company tried handling problems the way it had always handled them.

"We cleaned and scraped the tanks and chip conveyors when the coolant systems were changed," Don Stankus, Tier ONE’s director of manufacturing and facilities, said.

That led to more frequent waste removal, the purchase of replacement coolant, and extra labor.

The company tried to evaporate water-based coolants, but the process couldn’t keep up with the demand for disposal. The disposal of a 1,500-gal waste tank every six weeks cost $2,500 each time.

"We worked with our supplier and tried to get their help managing the coolant, but they said Tier ONE’s use of way oil and other metalworking fluids was its own responsibility," Stankus said. "When tramp oil wasn’t separating properly from the coolant, they told us to try aerators, skimmers, and more fungicides."

Taking the supplier’s advice, Stankus and his team began adding a fungicide to the coolant tanks. In particular, the fungicide needed to be used monthly on a number of the larger milling machines. But, in order to mix the fungicide properly, machines had to be shut down for up to 48 hours before flushing and recharging.

As if the lost productivity wasn’t enough, Tier ONE still discovered a build-up on the inside of machines. The shop continued to have a distinctive odor, especially after the weekends when the machines sat idle.

"At the time, we thought all coolants had this issue and this was just a cost of doing business," Stankus said.

Searching for another alternative, the company team researched coolant options. The team interviewed coolant suppliers and explained the shop’s issues. After preliminary research, they put coolants from two suppliers on trial for six months. They tested machines that had the heaviest coolant use and experienced the most coolant-related problems.

"We went slowly, not knowing the impact that changing coolants would have on the machines, parts, or tool life," Stankus said.

He and his team monitored coolant percentages, coolant life, and reaction to the machine and tools. After two months, the first coolant developed issues that concerned Tier ONE: It was flushing lubrication properties from the machine, so the tools were developing rust and locking in place.

Cool Runnings

The second coolant, Hocut 795-B, a biostable coolant from Houghton International, Valley Forge, PA, met with success. Hocut’s lubricity was high enough to keep the machines running smoothly without the problems of the other coolant being tried.

During the trial period, a Houghton rep made frequent visits to the company to perform chemical sampling of the coolants. After the changeover, he continued to visit monthly to check for problems and monitor some of the machines, Stankus said.

Although the new coolant cost about the same as the product previous used, the cost savings with the new coolant offered less frequent waste removal, longer coolant life, elimination of fungicides, and improved manpower efficiency.

Because the biostable coolant stayed fresh during use, Tier ONE did not have to regenerate coolant tanks each month. In fact, some of the tanks have lasted more than a year before the plant has had to change them. This has led to a cost savings of about $21,000 a year in waste removal.

Due to the replacement coolant’s efficiency, the company only needs to run its machines at six to 12 percent coolant. Because of its biostable properties, the company saved an additional $2,000 it was spending on fungicide additives to prevent build-up.

The shop also saw labor cost savings for coolant maintenance. Coolant changes used to require a full-time employee, but because fewer cleanouts occur, the employee can devote time to other tasks. Houghton International

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