OEMs Get Higher Speed, Longer Component Life with All-Ceramic and Hybrid Bearings
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Custom Manufacturer's Low-friction Bearings Eliminate Need for Oil and Grease in High-tech Applications
The manufacturing of precision, high-tech bearing components is a science that Champion Bearings, Inc., takes seriously. A custom bearings manufacturer in Palm Springs, California, Champion Bearings combines an innovative approach to design with the ability to work with a multitude of exotic engineered ceramics, plastics, and coating materials. The company produces components in sizes from miniature to massive.
“We can make bearings that fit into a wrist watch, on up to bearings that are 2-½ feet in diameter that are used in giant electricity-generating windmills,” says Richard Kay, Champion Bearings CEO and chief engineer. “What we typically produce are custom-made, ceramic, specialty ball bearings for high-tech applications. Our bearings can be used for harsh environments, for high-speed applications, machinery with high loads, high- and low-temperature applications, and for machinery used in a vacuum. We also do a lot of work for other bearing manufacturers that can’t handle the more precision work with special requirements.”
Champion Bearings has been in the forefront of bearing technology since the company’s inception in 1979, when Richard Kay, a graduate of Michigan Tech University, started the company in Palm Springs. Much of his approach to bearing manufacturing has to do with the theories of tribology, the science of friction, wear, and lubrication, a discipline in which he earned an honorary degree from MIT.
“I don’t have any proprietary technology because I don’t believe in hiding what I do,” says the company’s CEO. “If the technology’s going to get out, it will get out. My ion-deposition process could be called proprietary, but it’s so complex that I doubt if anyone could figure it out.”
With Bearings Like These, Who Needs Oil and Grease?
Kay believes that ceramic bearings can even play a part in reducing the use of fossil fuels in the industrial sector. “If manufacturers in the U.S. converted from steel bearings to ceramic bearings in just one size of bearing, I feel the country could save over one million barrels of oil per year,” says Kay. “To back up my theory, I went to the Federal Trade Commission to see how many metal ball bearings are sold in the U.S. in one year. They told me it was 600,000,000. If they are all ¼-inch or ½-inch, I figure it would take one million barrels of oil to lubricate them.”
Kay explains that hydrocarbon lubricants smooth out the surface of metal bearings, which have peaks and valleys that are visible under a microscope. Hydrocarbon or fluorocarbon lubricants are often used to fill in the valleys to keep the peaks from touching. But he believes there’s a better way of handling micro-weld adhesion.
“The area of contact is so miniscule that, for example, a force of ten pounds on the bearing generates a pressure of over a million pounds per square inch,” Kay theorizes. “What happens when the peaks touch? Without any oil or grease, they weld together. The welds will constantly break free and reconnect. This micro weld adhesion generates very high heat on the bearings.
“When I take the very same bearing and do the very same test using ceramic ball bearings with ceramic races, the heat is so minimal that you can hold them in your hands because they’re not hot,” he continues.
“With ceramics, you don’t get micro weld adhesion; therefore, you don’t need oil or grease. A lot of engineers think that oil and grease is needed to make a bearing go faster, but the opposite is true; it makes it go slower.
“Mechanical engineers are continually bombarded with data on various types of oil and grease lubricants for use in a variety of machines and, of course, ball bearings. All this data is superfluous with respect to ceramic ball bearings. Ceramics are lighter than steel with a lower coefficient of friction and little thermal expansion. And ceramics mean higher speeds, hardness, and durability, and they never rust. Ceramic bearings also work very well in vacuum chamber applications, since the oil and grease on metal bearings will outgas. And ceramics are also resistant to acids, alkalis, and salts.”
In one test that Kay performed, he tested a flywheel with a load using ceramic bearings and races, which are mounted on a trunnion. He brought the flywheel up to 7,000 rpm, and then measured the coast down time. “It took 350 seconds for it to stop rotating,” Kay maintained. “When I did this with metal bearings and races with oil and grease on them, they slowed down in less than 60 seconds. So this is a huge amount of torque and energy being absorbed by the system.”
Ion Deposition Process Provides Dry Film Lubrication
Richard Kay and his small staff do all of the designing, engineering, and prototype manufacturing in his small plant in Palm Springs, using mostly CNC milling machines and lathes. About four years ago, Kay was asked to make a ceramic ball bearing component for an electric motor that goes into a mechanical heart. “Six people are walking around on the east coast today—completely well—using the heart that has our bearings inside it,” Kay stated proudly. “It’s very exciting to see this application of our ceramic bearings.”
For some applications, Champion designs components using metal balls and races that are coated with an ion deposition process that they’ve developed. This is a dry film lube process whereby one material can be coated on top of another to fill in peaks and valleys. To achieve this ultra-thin coating, the inner and outer races and balls are inserted in a vacuum chamber, and then one of about ten different coating materials are applied, depending on the client’s application. The usual coating is about 2,000 angstroms thick, so the dimensions of the parts are changed very little. Possible coating materials include lead, titanium nitride, silver, tungsten disulfide, molybdenum disulfide, and carbide diamond. These materials have a variety of different properties, including decreased electrical resistance, wear resistance, corrosion resistance, high-temperature resistance, nonmagnetic and minimum out-gassing, low friction, higher strength, and non-reactivity to acids and water.
After the balls and races are coated, they are heated up until the material starts to boil. Next, the parts are zapped with 50,000 DC volts inside a vacuum chamber that has been flooded with liquid nitrogen for better conductivity. The ionized chemicals are now permanently bonded to the parts. The process fills in the peaks and valleys of the parts, in a manner similar to using oil and grease.
Specialty Bearings for Diverse High-tech Applications
Sometimes, the company will use ceramic balls in metal races coated with ionized chemicals to create a hybrid bearing component. The hybrid bearing includes a vacuum-compatible, self-lubricating molybdenum disulfide retainer, which requires no hydro or fluorocarbon lubrication. Since there is no metal-to-metal contact between balls and races, scoring is eliminated, and the component runs cooler with the absence of micro-weld adhesion. Other benefits include operating life three to five times greater than chrome-steel balls because wear is lessened; a reduction in heat generation; and low friction that allows for low torque. In addition, the hybrid bearings are 60% lighter than steel, which reduces centrifugal forces and overall system weight. And because ceramic bearings are lighter, they spin more easily and faster. A special, non-contact, Teflon®-fiberglass seal can also be inserted to keep dirt out of the bearings.
Champion Bearings produces finished components for a very diverse marketplace. “We do a lot of work for Maxum Motors, both AC and DC motors, and with Optical Coating Laboratories Inc., (OCLI), a company that makes optical lenses, many of which are used in vacuum chambers,” says Kay. “Our bearings are used to very precisely position the lenses for etching processes. We also make very clean bearings for the semiconductor industry for their chip-making machinery.”
Mechanical Equipment Co. is one of Champion’s highest volume customers. The OEM builds large air compressors, which need many angular-contact ball bearings, for industrial and commercial uses. Champion has developed specialty ball bearings for NASA satellites (the ultimate working vacuum) and recently produced, for a Department of Defense subcontractor, specialty bearings to be used in the M1-A1 Abrams main battle tank.
Champion can also work with a customer’s existing parts to retrofit them for enhanced operation. “In one instance, a customer had some seals that were leaking oil, so we added Teflon seals to the bearing,” Kay explained. “We also make angular [contact] ball bearings with a Teflon seal.”
Design and engineering is a key element for precision, high-tech bearing applications. When designing a new bearing, Kay first asks his client about the environmental conditions in which the bearing will be used. Is the environment hot or cold? Are oil or other hydrocarbon lubricants present? What speeds and loads will the bearing be subjected to? In some cases, the company’s engineers will have to design a retainer ring to hold the bearings for speeds over 1,000 rpm. And engineers will need to know what the machine’s shaft dimensions are so they can figure out what the OD of the bearing will need to be based on certain restrictions.
Champion makes a multitude of high-precision specialty bearings, quite often used for experiments in high-vacuum applications or with laser technology, for Cal Tech, MIT, and other universities. Some of these bearings are made with Stelite, a material often used for lathe tool cutting tips. The material has no iron in it, so it is nonmagnetic, but is capable of holding very high temperatures, up to 2,000 degrees F.
Many intriguing engineered materials, ranging from plastics to ceramic materials, such as zirconia, silicon nitride, and silicon oxide, are available these days. Amazingly, these ceramics are much harder than steel. In one test, Kay took a ¼-inch diameter ceramic ball bearing, put it on a steel plate, and hit it with a 35-pound sledge hammer. He said he could not break it or even put a scratch on it.
Engineered plastics, such as PEEK, Teflon, and Vespel are also used extensively at Champion. The company has recently developed a Teflon molybdenum disulfide material suitable for retainers. Kay recently talked to ten engineers at OCLI. He convinced them to use a zirconia ceramic for a particular bearing application.
“The thermal expansion characteristics of zirconia are almost identical to their stainless steel housings,” Kay explained. “Their application is at 250 degrees C. My zirconia bearings will expand at the same rate, so they won’t have any problems with the housings.”
Ceramic bearings would seem to be a technological phenomenon whose time has come for a variety of applications. From saving fossil fuels to creating long life and less friction for machinery, ceramics can be considered a viable solution. Champion Bearings, no doubt, is at the forefront of this technology.
Teflon and Vespel are registered trademarks of DuPont.
PEEK is a trademark of Victrex PLC.
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