When Dexter Magnetic Technologies, Elk Grove Village, Ill., introduced a dual axis robotic manipulator to control sputtering in the manufacturing of computer hard drives, it relied on a sophisticated drive and pulley system that all too quickly developed a troublesome, excessive wear problem.
A self-lubricating, anti-backlash gear from Intech Corp., replaced the complex pulley drive-train originally used to increase wear and reliability of the dual axis robotic manipulator that regulates the sputtering of computer hard drives in the HDDR industry.
Chris Ras, product development manager at the company, describes the drive system as “consisting of two single sided timing pulleys configured into two independent drive sections, each of which uses two single-sided timing belts.“ During tests at a customer’s plant, the faster of the two compact belt drives required frequent and precise tensioning to eliminate belt stretching and excessive wear.
Ras, in exploring a gear design as an alternative to the belt drive, contacted Tody Mihov, engineering manager, Intech Corp., Closter, N.J., to discuss how self-lubricating plastic gears might work into his design. The constraints of the application were limited space and a need for high torque and reversing torque. In addition, the gears would have to be retrofitted into existing equipment at the customer’s facility.
After reviewing load data through Intech’s proprietary gear calculation program, which was co-developed with a leading university, Mihov determined that the gear would work. He then improved the load carrying capacity of the Power-Core™ gears by applying a plus/plus gear mesh modification to the gear train.
The addition of two stainless steel drive gears to a Power-Core™ idler gear with an integral stainless steel core and a proprietary backlash-free plastic gear design assured the desired smooth manipulator motion. In addition, a special idler gear shaft made retrofit easy.
An in-house test determined gear performance relative to visible wear patterns and drive efficiency. Ras found that the drive efficiency increased by 15%. He reasoned that this was achieved in part by eliminating the radial stresses that belt tensioning transferred to the bearing. With the Power-Core™ gears running stress-free, the only force transmitting onto the mating gear teeth was the torque, which traveled on a precision-machined pitch line.
Filed Under: Factory automation, Gears • gearheads • speed reducers, Motion control • motor controls, Mechatronics