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Will MQL Adoption by Ford Help Drive the Process in the U.S.?
Author: Brian Lane
Source From: IMT Machining Journal
Posted Date: 2013-12-06
As part of a continuing effort to further green its operations, Ford Motor Co. plans to reduce the water used to lubricate machinery at six of its manufacturing plants by implementing minimum quantity lubrication (MQL).
“Reducing the environmental footprint of our plants is a critical part of Ford’s overall sustainability commitment,” said Andrew Hobbs, director of Ford’s environmental quality office. “Expanding new processes such as MQL across our global network of facilities allows us to have an even greater impact.”
MQL not only limits environmental impact, it can also foster employee health, reduce costs, and keep plants cleaner, say proponents.
Flood coolant is a standard method of cooling the work area during machining. Thermal warping and microfracturing caused by the friction that builds during machining are major factors that degrade quality. Microfractures can shorten tool life and, if not treated, can lead to machine down time. Applying coolant in a broad stream keeps thermal effects low.
However, flooding coolant has drawbacks. For one, its disposal is a government-regulated procedure that can impose high costs on manufacturers. While there are methods of recycling lubricants by filtering out particles, most lubricants must be discarded after one use.
Additionally, flood coolant can spill or splash onto factory floors, equipment, and workers.
MQL applies environmentally safe lubricant directly to the tool and workpiece in low amounts, replacing water and oil usage. The technique is touted to often work as well as, or better than, traditional flood cooling while providing environmental benefits.
MQL has yet to achieve global adoption. However, the process has been broadly implemented in Germany, where green regulations have forced manufacturers’ hands. Ford’s plan to use the method may signify a growing trend in MQL adoption.
“The Germans have done probably the most with MQL, because they’re driven by their green laws. They’ve spent a lot of money doing a big government study, going back and trying to help manufacturers adopt it,” Tim Walker, vice president of Grand Rapids, Mich.-based Unist, told ThomasNet News Machining Journal. “As a whole, the industry has been fairly cautious, and that’s why in the U.S., we don’t know (much about MQL).”
Walker has literally written the book on MQL, aiming to reduce many of the unknowns about the process and explaining near-dry machining to the uninitiated. Unist, which manufactures MQL products, offers free digital copies of The MQL Handbook on its website.
Unist’s particular MQL solution is a biodegradable, plant-based oil with properties enabling it to bond to metal surfaces and create a thin, low-friction barrier between the tool and workpiece. The lubricant is dispensed via precise, metered spray.
“If you’re doing true MQL, there is no disposal,” Walker said. “The amount is measured in drops per minute, and the parts should come out dry. If you use the standards the Germans use, they say less than 2 percent of the fluid remains on the part, so when it comes out, there’s nothing to dispose of.”
MQL uses about 1/10,000 of the fluid used in flood lubrication.
“If you’re doing it right you shouldn’t be able to see anything,” Walker said. “If you can see a mist, you’re using too much.”
Tool life preservation is also a benefit. German manufacturer Guhring, which produces aluminum casings for Ford, developed an MQL process that can achieve 1,200 mm/min and 1,400 mm/min feed rates, and claims an 0.18 mm wear rate after 100 minutes for tools, about 20 percent better than competing processes.
Ford is implementing MQL as an employee health measure, too. Standard coolants can cause skin irritation, including itching and redness. MQL generally uses vegetable or ester oils, or specialty materials like Unist’s Coolube, which do not irritate skin. Additionally, MQL uses lubricant in such small quantities that it typically does not come into contact with skin.
With these benefits, why is MQL adoption in the U.S. limited compared to flood coolant?
“I don’t think it’s a cost of implementing it as much as it is fear of the unknown in implementing it,” Walker said.
Introducing MQL is not trading one process for another, but involves a holistic analysis of a variety of aspects in a machine shop, he said. He hypothesized that some customers wary of the transition may take an “if it ain’t broke, don’t fix it” attitude.
MQL is not universally applicable, Walker acknowledged.
“MQL in general will cut warmer than with flood (coolant),” he said. This is usually not a problem, but some types of metal are more reactive to heat than others. “A lot of that heat […] stays in the chip. You get hot magnesium chips and guess what happens? They catch on fire.”
MQL is generally suited for operations using non-ferrous materials, steels, titanium, and specialty alloys, according to Unist trade documents.
But Walker is optimistic that Ford’s plunge into MQL will have a ripple effect.
“Because Ford took the time and money to go out and do this … when some of those leading companies go out and do this, the information will get out — they’ve done it, this works for them,” he said. “And they may say to their suppliers, ‘Hey, you might want to do this, too.’ ”
