Metalworking fluids have never been the most glamourous part of manufacturing. That’s been reserved for areas such as additive manufacturing, where complete parts are printed from a digital file, one layer at a time. However, most manufacturing today still consists of parts being cut, shaved or otherwise machined. As such, fluids remain a necessity for cooling and reducing wear of the machine tools doing the material removal—and there are constantly new developments in this area.
In recent years, tighter environmental regulations have encouraged the development of new formulas for fluids, as well as new ways to recover and recycle them. What’s more, performance demands on fluids have changed as some industries, such as aerospace, increasingly use difficult-to-machine metals such as titanium.
“Lubricants are as important as acquiring the best machine, tools, material and personnel to achieve the desired results,” said Edward Jones, chief operating officer of Hangsterfer’s Laboratories. “The lubricant side of the process is a very complicated one” from the start of production to a customer taking possesion of parts.
Fluid companies also say that non-petroleum products, while costing more initially, can ultimately be less expensive to use. For example, 5ME LLC says a Texas customer paid $24.28 a gallon ($6.41 a liter) for the company’s Cycle Cool 900, compared with $16 a gallon for the mineral-based fluid it previously used. But 5ME estimated the customer still saved 40% because of longer tool life, lower fluid maintenance and other factors.
What follows is a look at the strategies of some companies in the industry.
Mantua, NJ-based Hangsterfer’s forecasts an increase in demand for vegetable-based oils “not only due to the mandates that require the use of certain amounts of bio-renewable lubricants, but mainly due to their functionality,” Jones said.
“Modern forms of vegetable-based technologies often far exceed the capabilities of traditional petroleum-based products,” he said. “If any manufacturing company has not tested or at least evaluated vegetable-based products, they are probably passing up on some valuable performance benefits.”
At the same time, Jones said, “not all vegetable-based products on the market are the same. There still exist many products on the market that are best left for cooking not machining.”
Newer Hangsterfer’s products contain less than 10% petroleum, compared with older company products that have more than 60% petroleum.
The company’s newest coolants can “be run at higher concentrations to gain cutting performance benefits while not resulting in foam problems,” Jones said. Hangsterfer’s newest cutting oils have “much lower viscosities to allow better chip evacuation on small parts.”
The COO also said the company anticipates higher demand for its products “due to the increase of sophisticated metal alloys.”
New Providence, NJ-based Chemetall says it tries to anticipate new regulatory demands before they occur.
“What is the market going to want?” David Enright, business manager for metalworking fluids at Chemetall, said of his company’s approach. “What will be the impact of regulations? We tried to crystal ball that.”
Chemetall keeps an eye on what’s happening with regulators in Europe because new initiatives often start there, Enright said. For example, he said, regulations calling for boron-free fluids “started in Scandanavia, then moved into Europe.” Plants in the United States now want to avoid boron as well, he said.
“In general what we have done is have a good line of semi-synthetic fluids, very bio-stable,” Enright said. “We’ve managed to come up with a line of products that do not contain those materials.” Chemetall avoids triazine and kathon, he said.
Chemetall’s main product line is marketed under the Tech Cool name. The company now has 25 Tech Cool products without biocides out of about 100 total.
Salem, VA-based QualiChem has developed fluids that can be used in aerospace and other industries requiring more difficult-to-cut metals.
For example, the company’s Xtreme Cut290 utilizes ester chemistry which is “essentially creating a much more water-friendly vegetable molecule,” said Michael Forest, QualiChem’s director of metalworking. Xtreme Cut290, he said, “is compatible with all aerospace materials. No staining. No corrosion.”
QualiChem introduced Xtreme Cut290 five years ago. “Essentially, we’ve seen between double- and triple-digit growth for the past four years,” he said. The company has also developed a fluid marketed under the name Equ-Pure 450, which Forest described as “a full green product with no mineral oil whatsoever” and designed specifically for titanium and aluminum.
“It’s certainly becoming increasingly difficult for approvals” of fluids from aerospace companies in general, Forest said. “As aerospace companies need to maintain their profitability, they’ll look for better and better technology. The changes in the materials and designs of planes cause them to be more rigid and durable, the materials will be more difficult to manufacture.”
Cincinnati-based 5ME, a manufacturing efficiency company, has also been pursuing synthetic metalworking fluids, such as its Cycle Cool 900 series to meet the aerospace high-heat superalloy machining challenges.
“We’re gearing up for the aerospace engine manufacturing industry,” said Sonny Roy Truett Jr., the company’s Northeast regional sales manager. “You’ve got these machine tools pushing 1500 psi [10.3 MPa] through the spindle to reduce the heat at the cut, and fluid selection is critical. In regard to aerospace industry standards, not only does the cutting fluid need to run flat at elevated high pressures, but must pass stringent aerospace material compatibility and raw materials standards such as no chlorine or sulfur.”
5ME said the Cycle Cool 900 series is “low foaming” near neutral pH, and does not contain chlorine and sulfur and works with aerospace superalloys such as various grades of Inconel including 718 Inconel used in newer aerospace engines, along with titanium, hardened steels, beryllium copper, aluminum and stainless steels.
“If you have a mineral-based product and start machining at high speeds, you introduce a lot of mist into the air,” Truett said. “A lot of these [aerospace] companies are moving away from oil-based products due to the high level of fluid maintenance and the need to reduce oil mist in the air. We’re reducing mist to acceptable levels by replacing conventional mineral-based products with synthetic cutting fluids” such as the Cycle Cool 900 series.
“When you go into the aerospace industry, you have to change your mind-set altogether,” he said. “Their standards are much more stringent, and the materials are inherently more difficult to machine.”
Fuchs Lubricants “has only used vegetable oils on a limited basis for water miscible coolants,” said Jonathan Chow, product manager.
Instead of concentrating on changing the base oil of coolants, Fuchs’ development of products has been focused on additives, including synthetic esters, amines and fatty acids. The company, which is based in Germany and has a US headquarters in Harvey, IL, said using specialized additives is a better strategy.
The company’s newest product is Ecocool Global 10, aimed at markets worldwide. It was introduced in September and Chow says it has reached full-scale production. Ecocool Global 10 does not contain formaldehyde-based biocides, such as triazine, or boric acid, chelating agents, chlorinated paraffins, silicone, secondary amines and triethanolamine.
Ecocool Global 10 meets the chemical requirements of 19 major manufacturing countries, including the United States and European Union nations. The company said the product has resulted in longer tool life when machining metals such as titanium as well as softer metals such as high silicon aluminum.
Chow said that testing and application fees of major aerospace companies can run an estimated $100,000–$170,000 for full approval.
Aircraft manufacturers “are subcontracting work out more work than ever to Tier One suppliers,” Chow said. “We are seeing consolidation in the Tier One and Tier Two supplier base. This change, in turn, drives improvements in process control on the manufacturing floor and results in a demand for more reliable and higher performing machining coolants.”
Kalamazoo, MI-based PRAB produces systems to reclaim and recycle metalworking fluids. Reclaiming fluids from chips and turnings can be performed with wringer systems, where extraction occurs using centrifugal force, or briquetting systems, where extraction takes place with compressive force. The methods can remove as much as 98% of liquids from the material.
“We do work with a lot of coolant companies,” said Ron Chapman, a mechanical engineer with PRAB. “I’ve had them call me in and together we’ll develop a recycling package that will handle their particular coolant or cutting fluid type. Some fluids can be a challenge to recycle, but most all are recyclable. The key is to find the correct solution for each application.”
Adding a filtration or recycling system may cost some initial sales for the coolant company, but will raise its credibility with its customer base, while demonstrating its products are easy to recycle, Chapman said. Such systems can also increase tool life, result in a higher quality part and lower maintenance costs for customers, he said.
This article was first published in the March 2015 edition of Manufacturing Engineering magazine.
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