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A. Dirty coolant is delivered to the dirty side of the system by sump sucker or bucket.
B. The Suction Skimmer continuously skims the top most layer by suction rather than dragout.
C. The transfer pump moves skimmed fluids through the separator.
D. Crossflow Separator removes oil and solids by gravity only, without filters or coalescer media.
E-F. Clean treated fluids gravity flow E to the clean tank which continuously overflows at F to the dirty side for further processing.
G-H. Captured oil gravity drains automatically to capture barrel or tote G. Captured solids can be purged manually on demand through the angled bottom discharge.
I. Pump for filter circulation and return of clean coolant.
J. Bag filter using the recommended micron rating.
K. Optional magnetic separator.
L. Return line for clean coolants.
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Replacing tooling and machine covers is a necessary evil for CNC machine shops of all sizes, but many operators may not realize that certain metalworking fluids can shorten the life of these covers. With price tags running into the thousands of dollars, just a single new cover can put a hefty dent in a job shop's profits.
Such was the case at PHB Machining Division (Fairview, PA), which provides precision machining of small and mid-size castings for Motorola, Mack Trucks, Caterpillar and others. The synthetic coolant they used created a build-up on machines, causing a faster breakdown of the machine covers. At the time, the company didn't realize it could increase machine cover life by using a different product.
It wasn't until PHB's coolant vendor announced the discontinuation of the coolant being used that management discovered the difference a new coolant could make. In early 2006, Joe Smart, PHB's manufacturing manager, began searching for a new coolant. He was looking for a fluid that could run efficiently on 60 CNC machines that provided milling, drilling and tapping. Additionally, the new coolant would need to work on various metals, including 380 aluminum, cast iron, steel and Inconel.
After trying several coolants, Smart and his team contacted Houghton International, a provider of metalworking fluids and fluid management consulting, for a trial of its bio-stable Hocut 795-B coolant. After testing this coolant in six machines, PHB found the solution it was looking for.
After running with the bio-stable coolant for a few months, maintenance teams noticed something: not only were the machines experiencing less build-up from coolant use, but the machine covers were lasting longer. "We were going through $100,000 of sheet metal each year to guard the machines," recalls Gregg Workman, one of the CNC maintenance technicians. "Since switching coolants, our normal wear and tear only requires $20,000 of sheet metal annually."
Before switching to a bio-stable coolant, the evaporating water would leave an adhesive film on the covers. This would catch metal chips displaced during machining and slowly destroy the covers. The new coolant gives the covers more lubricity, so they are more durable than in the past. This has helped increase their life, according to Dave Fourspring, PHB machining supervisor. Today, the company spends 80 percent less on replacing machine covers than with the old coolant.
When the plant used the full synthetic coolant, technicians found silicone build-up in machine pumps. The coagulated mixture attracted metal chips, which became imbedded in the build-up. This contributed to less-than-ideal tool life and, after a while, the machines would lock up or crush metal. "Our maintenance group was hard on us for using the old coolant, because it was taking a toll on glass doors and rubber seals," notes Fourspring. "Our tool life was nowhere near as good as it is now running with the new coolant."
And because the new bio-stable coolant runs cleaner through the machines, the maintenance team saves more money on filters because they don't need to change them as frequently.
PLANT-WIDE TRANSFORMATION
After its long-time coolant was discontinued, PHB Machine got much more than it bargained for when it introduced the new coolant to its plant. Following the switch, PHB was able to:
• Reduce spending on machine cover replacements by 75 to 80 percent.
• Initiate a recycling program that helped cut its coolant spend by 75 percent.
• Cut the time spent on recycling coolant by more than 75 percent.
• Increase machine capacity by 40 percent since 2006.
• Create a safer work environment for all employees directly involved in machining operations.
• Reduce the environmental footprint, specifically CO2 emissions, associated with machining operations by maximizing the useful life of the coolant and thereby minimizing usage, disposal and transportation.
PHB and Houghton both strive for leadership positions in their sectors by developing strategic partnerships with clients and suppliers to reduce total operating costs, improve quality, reduce worker exposure and minimize the environmental impact of their activities. Since converting to the new coolant, PHB is already realizing many benefits associated with a cleaner machine tool environment. They also virtually eliminated the need to add dangerous chemicals to control the growth of biological organisms.
