As metalworking companies look to establish sustainable cost-saving measures, identifying ways to get greater mileage out of cutting fluids has become an avenue more organizations are exploring. It makes sense: adding or upgrading fluid recycling equipment significantly extends the life of cutting fluids and can decrease new fluid costs by as much as 75%.
One may wonder, how do metalworking companies know if the fluid recycling equipment is capable of effectively processing the cutting fluid so that it may be reused? The answer lies in testing the application's used cutting fluid prior to equipment specification.
Creating a Fluid Profile
Metalworking fluids are estimated to represent as much as 10% of the cost of a finished part. They also directly impact part quality-as fluid quality diminishes, the condition of the finished part drops. Additionally, when the fluid's lubricity decreases, motors are forced to work harder to operate the tool, increasing wear and tear on both the machine and the tool. With finished products and capital investments at stake, ensuring new fluid recycling systems can effectively treat the cutting fluid for reuse is essential.
Because the composition of used cutting fluids vary from application to application, an analysis of the metalworking fluids is a critical first step for creating an accurate profile of the fluid. For example, PRAB, a manufacturer of chip and fluid management systems, performs comprehensive sample testing to accurately understand the unique characteristics of a mixed solution and its industrial applications. The test results enable PRAB to determine the correct system design and capacity needed to optimize an operation's filtration processes.
The key to defining an effective treatment for cutting fluids is understanding how the fluid is being used in the application, and then establishing two benchmarks:
- How dirty is the fluid?
- How clean will it need to be for reuse?
To establish a characterization of the dirty fluid, the types of tests performed may include:
- Appearance: Noting color, transparency, type of fines and layers within the fluid that may include oil, an aqueous phase and sediment
- Acid split: Noting the split material such as product oil, tramp oil and surfactants
- Centrifuge: Performing an appearance analysis after running fluid through a centrifuge to determine the percentage of solids in aqueous fluid
- Meter: Measuring pH, total dissolved solids and conductivity.
Vacuum filtration, gravity settling and separatory funnel testing may also be utilized.
System Specification
Fluid recycling processes require oil/water separation, fluid filtration, bacteria elimination and coolant concentration control. Because the composition of used metalworking fluids varies so greatly, the correct system may require customization to treat a specific industrial fluid. Selecting the right combination of technologies for the application depends on several factors:
- The volume of fluid per hour
- Type of cutting fluid
- Amount of and types of contaminants
- Fluid filtration (micron) level
- Desired level of automation
- Desired total cost of ownership.
Fluid recycling solutions range from basic paper filtration to highly automated, centralized fluid-recycling systems that require minimal involvement from operators. Working with a trusted supplier with extensive knowledge in metalworking applications is critical to specifying the optimal system. For example, a PRAB system may include one or more of the following solutions:
- Centralized recycling system: Turn-key system that automates the removal of tramp oils and suspended solids from contaminated coolant with flow rates up to 1,500 GPH. It also controls bacteria and can adjust fluid concentration for fluid recovery.
- Tramp oil separator: Removes free-floating and mechanically dispersed tramp oils, bacteria, slime, inverted emulsions and more from individual machine sumps, central systems and wash tanks. Features flow rates up to 150 GPM. No consumable media required.
- Oil recycling system: Centralized turn-key system removes the suspended particles and moisture that shorten the useful life of oil-based fluids. Facilitates flow rates up to 30 GPM.
- Centrifuge: Suited for separating all types of ferrous and non-ferrous solids-including fines-from oils and water-based cutting fluids with flow rates up to 50 GPM. No consumable media required.
- Vacuum filtration: Eliminates high sludge volume produced in machining centers and grinding applications and can accommodate flow rates up to 3,000 GPM. No disposal media waste.
- Drum-type scraper separator: Removes aluminum, nonferrous and composite material contaminants from coolant with flow rates up to 370 GPM.
- Magnetic separator: Uses high-intensity ferrite or rare earth magnets to remove ferrous material, including sludge and chips, from both water-soluble and neat oils with flow rates up to 315 GPM. No consumable media required.
- Candle filter: Captures grinding swarf and fine particulate as small as 1 to 3 microns and accommodates flow rates up to 80 GPM.
- Hydrocyclone: Separates up to 98% of contaminants from water-soluble machining coolant with flow rates up to 74 GPM. No consumable media.
- Paper bed filters: Provides solid/liquid separation of ferrous and non-ferrous metals as small as 5 microns for grinding applications with flow rates up to 130 GPM.
Conclusion
The savings that a metalworking company can accrue by recycling its cutting fluids can easily amount to hundreds of thousands of dollars per year. By reducing new cutting fluid expenses, improving part quality, extending tool life and lowering cutting fluid disposal costs, fluid recycling systems create sustainable cost savings. However, ensuring the fluid recycling system is capable of the treatment necessary to make the fluid reusable is paramount. Analyzing the cutting fluid is an important first step toward achieving that goal. To learn more about PRAB's free fluid testing, visit prab.com.
Authored by Mike Hook, Director of PRAB Sales & Marketing
For more information contact:
PRAB Inc.
5801 East N Ave.
Kalamazoo, MI 49048
877-558-9834
sales@prab.com
www.prab.com