Page 19 - MetalForming March 2011

to the emulsion. In addition to their emul- sifying properties, these additives can contribute supplemental corrosion inhibition and lubricity to the finished metalforming fluid, offering lubricant formulators tools that provide multiple functions simultaneously. Newer product developments in emulsifier composi- tion include a focus on achieving mul- tifunctional performance and reducing the emulsion foaming tendency.”
The uncontrolled growth of microbes (bacteria or fungi) is one of the most common sources of emulsion degra- dation and reduced fluid-service life. Water-based metalforming-fluid emul- sions contain an ideal breeding ground for microbes to thrive: water, organic food sources from oils and other per- formance chemistries, and typically a slightly elevated temperature from the service conditions. To keep microbial growth in check, lubricant suppliers introduce biocidal additives to the recipe, either as a fluid concentrate or as supplemental tank-side additions.
“When applied properly, including biocide product selection and consid- eration of the correct treat-rate concen- tration, biocides will effectively control the growth of microbes and promote a longer fluid service life,” says Purnhagen. “All biocidal products are not equal, and the selection process must include knowledge of the compatibility with the overall lubricant formulation. For emulsions, biocides with solubility properties in oil and water can show superior long-term stability and deliv- er the best overall performance profile.”
Suppliers of quality metalforming fluids generally include some degree of service or training so that biocides are used safely and effectively with their particular products. The results of uncontrolled microbial growth can include product performance degra- dation, emulsion instability, loss of cor- rosion protection, foul odors and irri- tation or illness for shop-floor workers.
Success in the Field
To learn how lubricant formulators are developing new recipes using addi- tives from Lubrizol and other suppliers,
we spoke with two Northeastern-U.S. companies that formulate and blend lubricants, coolants and cleaning com- pounds for metalformers, machine shops and others: Harry Miller Corp., Philadelphia, PA, and Angler Indus- tries, Sterling, CT. Top of mind: recent EPA scrutiny of short-chain chlorinat- ed paraffins, popular additives in met- alforming lubricants.
“Additive suppliers have been mak- ing concerted efforts to develop replacement additives for chlorinated compounds,” says Nick Ariano, tech- nical director at Harry Miller, “and we’ve had success in several cases for metal stampers formulating lubricants with these new additive packages.”
Describing such successes, Ariano explains how one customer recently replaced a chlorinated lubricant with a nonchlorinated product in a wire-shav- ing application performed to remove the outer layer of scale. And in anoth- er case, dating back to 2008, this one a Pennsylvania metal stamper forming heat-exchanger parts “with a lot of dim- ples and cup-shaped forms,” Ariano says, “a nonchlorinated lubricant replaced a chlorinated product and the company has had a great track record with the lubricant ever since. Payback for the new lubricant came quickly thanks to reduced waste-disposal costs, with no loss in performance.”
Severe Deep Drawing Still Requires Chlorinated Additives While these two success stories
make a great case for the metalforming industry’s efforts to become more envi- ronmentally sound, the job is far from complete. Tony Kroker, a regional man- ager for Harry Miller Corp., explains:
Carby Corp., Watertown, CT, a deep-draw stamper operating some 70 Waterbury Farrel and U.S. Baird transfer presses, used to blend its own lubri- cants, but as suppliers of com- pounds started to discontinue some of their ingredients, the stamper looked to outsource lubricant formulation. One par- ticularly challenging job Carby runs: severe deep-drawing of cosmetic brass parts, for ink pens.
“In simpler stamping applications, we can readily substitute for chlori- nated paraffins (with ingredients such as sulphurized compounds, synthetic esters and calcium sulfonate), with great success. But in more challeng- ing applications, such as deep drawing, compounded by the growing use of tougher materials such as stainless steels and cosmetic brasses, we’ve developed water-soluble draw lubri- cants that actually have an increased concentration of chlorinated paraffins. In these applications, we find that while we’re not able to eliminate chlorinated products from the lubricants, we are able to switch metalformers over from straight oils to a water-soluble product and provide a more cost-effective prod- uct that’s more environmentally sound and allows for easier cleaning. And, since the lubricant contains water, in many cases the presses can run faster.”
Adds Ariano: “In these severe cases (as described by Kroker), the issue is not so much lubricity or the ability to draw the materials. The hurdle with nonchlorinated lubricants, so far, has been stickiness of the stamped parts after forming, as metalformers look to conduct post-forming tasks—stacking and destacking, assembly and the like.”
“Replacing chlorinated paraffins in severe draw applications is an ongoing project,” shares Harry Miller president Bruce Entwisle, “and the technology has a long way to go to allow formula- tors to deliver effective and affordable lubricants. But I see the time coming— there’s a lot of research and develop- ment work going on.”
Angler’s Bob Bristol, vice president of operations, agrees. “Additive suppliers are developing new, useful products
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