Miniature direct-drive linear motor shrinks automation systems

April 20, 2007
Copley Controls paves the way for decisive automation advances with its new ServoTube small-silhouette STB11 linear motor. The direct drive size 11 motor combines a slim form factor with superior control stiffness, unmatched bandwidth, and ±12 microns positioning repeatability. STB11's combination of simplicity, reliability and dynamic performance enable fast-response digital servos to replace complex, wear-prone electromechanical assemblies. The motors are IP67 rated and are food-safe. The STB11 motors provide ten times the speed and ten times the life of ballscrew actuators. STB11-based positioning stages have the same form-factor as ballscrew actuators, enabling an easy migration to next-generation performance. Shrink Real Estate Motor compactness-forcer width is only 26 mm-provides benefits in applications where space is critical and costly: desktop, benchtop, and laboratory applications for example. STB11 motors lend themselves to integration into compact systems used for inspection, analysis, assembly and packaging. Their small silhouette translates into more production per square foot in hosts of space-critical applications. Rapid Acceleration The motor's combination of powerful drive force and low mass enable it to accelerate light loads to 25g. Specifications include stroke to 372 mm, 46N-to-92N peak force, and 3.1-to-5.2 m/sec maximum velocity. Thrust rod diameter is 11 mm. Rugged, Cost-Effective, Easy to Install The motor's integral solid-state position sensor eliminates the expensive and delicate external encoder traditionally required in linear motor systems. Installation is simplified, cost reduced and the inherent ruggedness and dependability of the STB11's simple two-part construction is fully realized. Direct Drive Positioning The motor's load-positioning forcer is driven directly by the interaction between its permanent magnet and electrically energized magnetic fields. There are no intervening gear trains, ballscrews, flexible couplings or drive motors to add inertia and impair responsiveness. STB11's permanent magnets are sealed into the stainless steel thrust rod. The load-carrying forcer travels on a low friction single rail bearing; motor drive coils are encapsulated within the forcer, which travels in free air and acts as an efficient heat dissipater. Powerful Controller Users can optimize servo position control by matching STB11 motors to Copley's Accelnet digital controllers. Accelnet controllers provide powerful stand-alone and multi-axis control choices; networking options include CANopen, Ethercat, Macro and DeviceNet. Operated from DC power supplies, the controllers deliver the 70V power needed for optimal motor performance. Applications ServoTube 11 motors, with fast-acting, direct drive digital precision, are natural candidates to replace complex electromechanical assemblies. The motors shrink space requirements in semiconductor, medical, pharmaceutical, printing, assembly, dispensing, and packaging automation. They are free from the friction and wear that undermine repeatability and dependability of ballscrew and other positioners.