Napoleon Engineering Services provides insight into manufacturing of custom bearings
As global bearing giants increase their global footprint and concentrate on core product lines, the sources for custom bearings solutions has diminished significantly. In the past, it was common for bearing manufacturers to publish catalogs listing all of their nonstandard bearings for a variety of applications. Today, most “special” catalogs have gone out of print and so has the desire to make these bearings due to small production quantities and loss of original manufacturing capability. The exception is Napoleon Engineering Services (NES), the proud US manufacturer of custom ball and roller bearing solutions.
According to NES president and chief engineer, Chris Napoleon, “There is no demand shortage in the market for high temperature, corrosion resistant, high fatigue life, and dimensionally unique solutions for industrial and aerospace bearing applications. That’s why we developed Denali Bearing Solutions.”
Denali Bearings, manufactured in Olean, NY, stand for more than just custom bearings with unique characteristics or features to work in tough applications. According to Napoleon, “It also represents our philosophy of retracing the roots of our original bearing manufacturers in the US that placed a tremendous value on service. Where service means picking up the phone in two rings, listening to the customer, making what the application needs through proven engineering and manufacturing solutions, incorporating unique materials, processes and configurations into the design, and having regular communication with the customer about manufacturing status. It’s also important to provide additional services such as failure analysis, product testing capabilities, first article inspection, and material and process traceability. To do this and deliver the quantity that’s needed within a short time frame makes the overall experience more personal, satisfying, and reliable as opposed to buying a commodity and hoping it will work.”
The Denali Bearing product and philosophy is not easy to execute and that’s why few have the capability to offering these services. Understanding the resources and steps necessary to manufacture a custom bearing reveals how challenging the Denali Bearing Solution is to produce.
The first step in creating the Denali Solution was to establish broad manufacturing capability in soft turning, heat treating, hard turning and milling, grinding, nondestructive testing, specialty processes, superfinishing, inspection, and testing across a variety of bearing types in need of customization. They include deep groove, angular contact, thrust and self-aligning ball bearings, cylindrical roller bearing and needle roller bearings. Having manufacturing capability to produce this wide range of parts in size ranges from 20mm through 350mm outside diameter provides a lot of options for NES to support the custom bearing user. Over the last 10 years the development of hard turning and milling to incorporate unique physical features after the hardening process has really benefited the custom bearing manufacturer. Adding anti-rotation features, provisions for bearing monitoring devices such as thermocouple and accelerometers, offset flanges, oil lubrication ports, puller grooves, and threaded mounting holes are all possible through hard machining that was once very time consuming and costly to produce.
Being able to manufacture special configurations is important and valuable but it’s just the start. There are a variety of bearing steels available beyond the ubiquitous 52100 and 440C steels that offer enhanced operational benefits. If corrosion resistance is critical to bearing life within the operating environment then NES has several materials and heat treatment processes that maximize the resistance to corrosion. From space to medical applications the use of 440C is commonly used. But there are much better choices for improved corrosion resistance and wear resistance. The use of Cronidur® 30 and XD15NW are superior in both categories over 52100 and 440C. NES has heat treatment processes that maximize specific operational benefits related to corrosion resistance, fatigue life and high operating temperature. NES has also been working with NASA to manufacture bearings made from Nitinol 60, a unique material with the highest corrosion resistance capability of any rolling element bearing material available today. Nitinol 60 also possesses super elastic properties providing significantly higher resistance to true brinelling making it of particular interest to the space community due to launch load conditions. The challenge with this material is holding the bearing during machining. Conventional techniques using magnetism are unusable since Nitinol 60 is completely nonmagnetic. As a result NES has developed proprietary work holding techniques for use with its CNC grinding machines. The nonmagnetic characteristics, though challenging to the manufacturer, offers another unique product solution for NES application engineers and their customers.
NES has observed two situations that often require the use of specialty bearing materials. When existing equipment is pushed to extreme operating limits to increase machine output this results in increased loads and temperatures yielding thin life margins. The other situation involves new equipment where bearing design analysis is left to the end of the development process creating physical size constraints for the ideal bearing. In both of these cases the use of high fatigue life bearing steels can save the day. High life steels such as M50, M50NiL, and Pyrowear® 675 are a few of the materials NES can choose from to bolster bearing life. Using premium through and case-hardened steels, special heat treatment processes, and platings such as Titanium Nitride on cage wear surfaces allows for incredibly high life adjustment factors over standard bearing steel. “Increasing bearing life by more than 20 times yields huge operational benefits to the customer,” says Napoleon. Again, these materials are not easy to work with and require significant attention to detail in design of stock allowances and material removal after heat treatment to ensure surface, subsurface and core material properties.
Another area of interest to NES, which is often overlooked is the importance of the cage that maintains rolling element separation and proper load distribution. Cage material, coatings, additives, clearances and lubrication provisions all play a major role in establishing and maintaining optimum bearing operation and offering the strength needed with minimal friction.
“Designing a bearing using specialty material is rather easy,” according to Napoleon. “Having the right manufacturing operation and process technology is much more difficult. But when you can combine those two elements with an emphasis of servicing the customer, you find people lining up at the door looking for the Denali Bearing Solution.”
by NES president and chief engineer, Chris Napoleon