3D printers are a cutting-edge manufacturing technology, but they must adhere to traditional equipment design rules. They need bearings to allow motion, and these bearings require lubrication. Oil and grease are typically used … but both are notoriously messy and can migrate from the bearing — in turn contaminating the machine and workpieces. Such contamination is tolerable on certain industrial equipment, but contamination of a product in a 3D printer setting can degrade the product itself during the building phase.
One 3D printing company in the southeastern U.S. recently had this oil-contamination problem with bearings on their printer-wheel carriage arms. The linear-motion axis bears relatively light load (20 kg) but runs at high speed (500 mm/sec) which leads to high temperatures (to 662° F). So bearing lubrication was transferring onto the molded product during tests — an unacceptable contamination.
The additive-manufacturing company tried running the axis unlubricated, but the high speed and temperature quickly led to bearing failure. The company’s engineers also unsuccessfully attempted to design their own auto-lube system to fix the problem. Finally, they tried oil-impregnated metal bushings, but these wore out too quickly due to the high speed. An entirely new bearing solution was needed.
That is when the 3D-printing service provider turned to Graphalloy, a specialty-bearing company offering a graphite-metal alloy by the same name.
Graphalloy comes in more than 100 grades, and all are self-lubricating, non-galling, and dimensionally stable. This stood out as a bearing solution for a couple of reasons. The material does not require traditional lubricants that can contaminate the precision molding process. It could also handle the high linear speed and high temperature of the application. More specifically, Graphalloy materials can operate at temperatures to 1,000° F, far above the operating temperature of traditional industrial lubricants.
The company’s engineers tested Graphalloy GM 111.3 bushings in this application for more than a year and remain very satisfied with the bushings’ life. In fact, the original test bushings are still used on their prototype 3D printers with virtually no wear.
Currently the design engineers forecast a life of one year on the new bushings with the machines running at full production capacity.
The company uses the 3D printers for on-demand manufacturing, which includes anything from prototypes to replacement parts for all types of industries — including the fast-growing medical-device industry. This is a world where research, design, and production are happening at lightning speed. Such innovations should not be limited by motion components. For more information, visit graphalloy.com.
This story was written by Graphalloy assistant general manager Colin Walker. Walker works with customers to improve their equipment performance through the application of Graphalloy’s innovative materials. He has a BA from Trinity College and an MBA from Columbia University, with a concentration in Operations Management.
