Consider the “No Touch” Solution
Air bearings may be the right answer in automation settings that demand high precision and low upkeep.
Excerpted from the Design News Feature Article by Lawrence D. Maloney
While still dominant in the semiconductor industry, air bearings are now tackling positioning challenges in applications ranging from food processing to medical.
More engineers are choosing air bearing systems, particularly in designs that call for zero-maintenance, long-life performance. Other designers like the positioning advantages of air bearings. Without friction, air bearing stages don’t need to overcome resistance when making small point-to-point moves or when maintaining precise speeds, as in scanning applications.
Not that air bearings will ever supplant precision roller stages in most applications. “I encounter air bearings in perhaps 5 percent of my motion control applications,” says Todd Shearer, senior application engineer for Galil. “Typically, you’ll see air bearings on one axis of a multi-axis system where you need smooth, low-speed motion.”
What applications stand to benefit most from air bearing technology? To find out, Design News got the following reports from leading companies in the field.
New Way Air Bearings: Broader Application Mix
At New Way Air Bearings, company founder Drew Devitt reports a surge of new orders from applications outside the precision marketplace, such as “no-oil” environments. The food industry-in particular the processing of flour, wheat, and sugar-see air bearings as delivering significant advantages, says Devitt.
Traditional bearing surfaces require oil to maintain function, but dry process dust is attracted to that oil, creating a troublesome slurry where the processed material meets the lubricant. Result: a maintenance nightmare. With continuous air flow through New Way’s porous media, the bearing surface is self-cleaning, which reduces down time and maintenance costs.
Another key application area is Free Abrasive Lithographic Patterning (FALP), a high-precision process for producing semiconductor components. CoorsTek, Golden and CO, use FALP to manufacture patterned ceramic components for the LCD and semiconductor industries. “These products are manufactured from high-purity ceramics, using the most advanced precision machining and grinding equipment available,” notes Steve Williams, sales manager for CoorsTek. “Precision, speed, and repeatability are critical to our process, and air bearings deliver on each of these requirements.”
He adds that air bearings represent the only viable solution for such a dry, abrasive, oil-free environment. “Without the air bearing, the free abrasive media would quickly destroy the machine,” says Williams.
Devitt sees the pairing of ceramics with porous media air bearings as a natural fit. “CoorsTek also manufactures metrology and machine components,” he explains, “so they understand accuracy. Combined with our air bearings, the high stiffness-to-weight ratio and micron-level precision of CoorsTek ceramic beams and stage components provide unsurpassed accuracy and reliability.”