Nearly a decade ago, a manufacturer of optical inspection equipment came to us with a dilemma: Its equipment was having problems, well, focusing.
Despite incorporating state-of-the-art technology into the product¡¯s overall design, the focusing mechanism was underperforming. It wasn¡¯t a reflection of the lens itself, whose materials and workmanship were industry bests. Rather, as the overall mechanism required smooth, incremental movements powered by a minuscule motor, it was highly susceptible to the slightest variations in starting torque. This made it a bearings issue.
AST initially introduced higher precision catalog bearings, but the motor couldn¡¯t generate sufficient power to drive the mechanism consistently. Additionally, despite a reduction in fill amount down to 10%, adding the requisite grease lubricant created drag that compromised functionality.
That¡¯s when AST engineers came up with a solution ¡ª use ceramic balls inside of the stainless steel rings to run the bearings without any lubrication. Typically, a bearing should run with lubrication, but in this case, the ceramic balls¡¯ lightweight quality and high polish helped to reduce torque without the need of lubrication (which had been causing drag). Additionally, engineers trimmed the bearing¡¯s ball complement from 13 to only five, while achieving precision and consistent movements with the focusing mechanism. The entire design took roughly nine months to complete, a process that included multiple levels of samples. After significant trial and error, AST arrived at a version that, nine years later, continues to perform.
AST¡¯s in-house capabilities, including a clean room, proved critical to the project¡¯s success. The ability to disassemble the bearings, replace the steel balls with ceramic balls, re-install the retainer, and perform the final inspection in a cleanroom environment made the entire process turn-key for the manufacturer, a rarity in the bearings industry.
This custom bearing assembly is still manufactured today, completely in-house (assembly, processing, cleaning). It has proved exceptionally durable while delivering uniformly consistent results.
When trying to find a bearings solution that minimized torque, engineers reduced the ball count and turned to ceramic balls, a lightweight material with a very high polish, which collectively reduced torque. Additionally, the dissimilar ring materials allowed the bearings to run without lubrication.
AST
www.astbearings.com
