In 2002, Eaton Corp.s manufacturing facility in Saginaw, Mich., experienced plantwide coolant problems that affected daily operations and profitability. Realizing it was time to explore new coolant options, the automotive hydraulic lifter manufacturer and its onsite fluid specialist welcomed the idea of trying new coolant technologies.
Plant operators considered many products that could potentially relieve the 174,000-square-foot plants coolant headaches, which included bacterial infections, dermatitis issues, swarf buildup, reduced tool life, ongoing system dumps and unpleasant working conditions. Eatons fluid specialist additionally sought to reduce overall fluid costs for the manufacturer.
The coolant we were using led to ongoing stability problems at the Saginaw plant, said Ralph Czolgosz, senior buyer for Eaton. We wanted a replacement that could improve tool life, increase system life, and eliminate our issues with bacteria.
Ultimately, the Eaton team learned that its coolant solution would not only rid the plant of its manufacturing woes, but was also environmentally friendly because it was vegetable oil based.
Down in the Dumps
In those days, Saginaws three central coolant systems – Henry I, Henry III and Henry IV – contained 100,000 gallons of coolant and fed five metalworking machines, performing processes such as broaching, mill cutting and grinding. Each system used a mineral oil based coolant. Quality of this coolant was crucial for the plants main product: hydraulic lifters used in automotive valve assemblies. Also known as lash adjusters, these required extremely precise machining and grinding steps, to tolerances as tight as 0.0001 inch.
With an average cost of $500,000 a year, coolant consumed 25 percent of Eaton Saginaws total annual chemical budget, said Brent Short, Houghtons global Eaton portfolio manager. In 2002, Short was the Houghton fluid specialist contracted by Eaton to manage fluids at the Saginaw plant. The coolant was the facilitys life blood to move production out the door and satisfy customer demand, he said. But when it failed, it meant a slowing – or even a halt – in production.
To keep bacteria in check, Eaton relied on packages of biocides (bio kits) comprised of chemicals that eventually made their way into Saginaws waste-water system. These quick fix biocides impacted relations with the city of Saginaw and became costly. Eaton shut down certain machines once a month for cleaning and to powerwash the trenches to remove fungi. System dumps of the former coolant reached from 70,000 to 80,000 gallons in 18 months for a single sump. Proper monitoring, management and machine maintenance generally allow a central coolant system to last anywhere from one to three years, but the stability and system longevity at Saginaw were not meeting Eatons or Houghtons expectations.
Partial system dumps were costing them heavily, and Eaton needed to reduce the amount of coolant and associated costs required to operate, said Short.
The expensive biocide chemicals, costing between $700 and $800 for a five-gallon bucket, also went down the drain with the lost coolant. The chemicals were so hazardous that plant personnel required a certification to handle them.
The coolant also affected machine quality. Eaton was replacing bearings every two years due to wear and tear from ineffective coolant. Bacteria caused scum buildup on the cutting edge of tools and impacted tooling quality. Parts required additional grinding to maintain quality control.
Serving as site managers, fluid specialists monitor fluid levels and test new technologies on an ongoing basis, with the goal of reducing fluid-related costs within a plant. In Saginaw, Eaton contracted with Houghton Fluidcare, fluid management specialists who surveyed all the lines, products and processes.
As Eatons Fluidcare specialist at the time, Short recommended ways to reduce costs and hazardous waste, improve output and solve the operator complaints. He also recommended a field trial of new coolant technology, with the goal of finding one that lasted longer and worked more effectively in all the systems without souring. As site manager, his priority was to find a single coolant that improved all of the different machining processes.
After a thorough product search, Short recommended a vegetable based coolant that contained technology field-proven to last longer in the machine sump than traditional coolant. With the prospect of improving costs and lessening environmental impact, Eaton was willing to look into this green option.
Battle of the Bugs
The Henry I and III systems, covering 596 and 1,288 square feet, respectively, supply coolant for multiple machining processes. Before switching coolants, these systems were producing a horrible odor caused by bacteria. The Henry IV system supplied coolant for grinding operations, which led to a buildup of metal fines. The existing coolant needed to manually bypass the system to control the level of fines.
After successful product trials, Eaton began to switch over its coolant systems to the new vegetable oil based fluid. Short tested for pH and completed a daily titration and acid split to test for coolant concentration. Each week, he tested for bacteria, using bio-dipslides.
The switch not only resolved the odor issue but also reduced tool usage. With the new product, Eaton achieved a consistent fines level of 300 parts per million. Easy removal of fines and heavies led to better grinding quality and a 90 percent reduction in dirt within the system.
The vegetable oil based coolant reduced friction at the tool and part interface, and enhanced heat transfer in Eatons high-speed operations. Eaton increased production throughput by $1.7 million per year. Without residue buildup on tools, it was able to achieve more parts per piece of tooling. Titanium nitride (TiN) coated mill cutters, which previously lasted 2,500 hits per tool, were lasting up to 5,000 hits per tool with the new coolant. Tool life became consistent, and less regrinding improved air quality within the plant. Bearings experienced less wear and tear. Overall, Eaton saw $250,000 in tool savings with the new coolant.
Soon after the switch, we began seeing huge differences that improved operations throughout the entire plant, said Czolgosz. We were able to discontinue use of two different biocide products fairly quickly, and both were very costly.
Eliminating use of biocides saved Eaton $40,000 a year, and plant personnel could also do away with the certification process required to work with the chemicals.
As in many facilities, Saginaw plant operators had experienced issues with bacterial infection. But after switching coolants, there were no outbreaks of new cases of dermatitis.
Value Versus Waste
When using bio kits with the previous coolant for bacteria control, plant personnel had to remove one-third of the system coolant with each monthly dump. With the new product, one of the systems operated on the same vegetable based coolant for three years without a single dump. In fact, the overall quantity of coolant usage was reduced by 50 percent. Eaton also saw a 20 percent reduction in coolant waste stream. In a single year, those savings totaled 120,000 gallons, or $12,000.
With the old coolant, Eaton treated waste internally before shipping it to the city for further treatment. An electric pump managing this process led to increased electricity costs for the plant. Despite the price and amount of man-power necessary, the plants waste production was too high to consider other options.
Using the green coolant, Eaton reduced coolant usage enough that it could haul 100 percent of the plant waste offsite. Plant waste production diminished so greatly by September 2006 that the plants consultant suggested that it would reduce costs further to outsource waste-treatment offsite. As a result, waste was treated a single time, and Eaton no longer had to rely on the city for any disposal.
Less waste and fewer chemicals at the Eaton plant meant that they were able to take responsibility for the sites environmental impact on Saginaw and surrounding areas. Despite higher costs per gallon often associated with green coolant alternatives, Eatons Saginaw location experienced cost savings so great that the plant served as model for Eaton manufacturing facilities worldwide.
Experts in Charge
The Saginaw experience with these fluids brought valuable lessons all around. Although that plant has recently closed, and the operation is relocating to a new facility in Aguascalientes, Mexico, Houghton Fluidcare was able to generate interest in this approach and put similar biostable fluids into use at other Eaton plants it serves worldwide.
What is it that made the transition from coolants so effective? Eatons philosophy allows for contracted consultants to take the reins.
Within Eaton, if a company manages a plants system, they are seen as the experts in charge, said Czolgosz. We allow and expect them to make recommendations.
Additionally, prior to the closing, Eatons success with switching to a green coolant led the plant to consider congruent, vegetable oil based hydraulic fluids, in hopes that chemical compatibility could further reduce chemical usage at all levels. The fluid consultant recommended this direction because with such a configuration, Eaton wouldnt need to strip oil from the coolant system and could avoid the resulting coolant loss.
Compatibilities will help limit consumption at all levels, and that is to everyones benefit, said Czolgosz.
That effort now moves to another arena, to build on the groundbreaking success at Saginaw.