Posted to News on 1st Jun 2007, 16:44
Direct-drive linear motor achieves 25g acceleration
A compact new direct-drive linear motor combines a slim form-factor with high speed and 25g acceleration. Copley Motion Systems' STB11 motors are claimed to provide ten times the speed and ten times the life of ball screw actuators, making them suitable for boosting productivity in high-speed point-to-point positioning applications.
STB11-based positioning stages have the same form-factor as ball screw linear drives, enabling an easy migration to next-generation performance. The motor's integral solid-state position sensor eliminates the expensive and delicate external encoder traditionally required in linear motor systems, making it rugged for applications requiring an IP67 rating. The elimination of external encoders also simplifies integration compared with traditional linear drive technologies.
The motor's load-positioning forcer is driven directly by the interaction between its permanent magnet and electrically energised magnetic fields. There are no intervening gear trains, ball screws, flexible couplings or rotary motors to add inertia and impair the dynamic response of the linear drive. The STB11's permanent magnets are sealed into the stainless steel thrust rod.
A low-friction, single-rail bearing carries the load-carrying forcer, and the linear motor's drive coils are encapsulated within the forcer. The load-carrying forcer travels in free air and dissipates heat efficiently without the need for forced convection cooling. This enables the STB11 to operate continuously at high duty cycles.
Exceptional repeatability
Like all the tubular motors in the ServoTube range, the STB11 features standard +/-12um positioning repeatability. The STB11's combination of simplicity, reliability and dynamic performance enable fast-response digital servos to replace complex, wear-prone electromechanical assemblies in pick-and-place arrangements.
Productivity can be increased where space is critical and costly, such as desktop laboratory automation machines, because the forcer width is only 26mm. STB11 linear motors deliver high-performance linear motion in a small unit for integration into compact systems for inspection, analysis, assembly and packaging. The speed and force of the STB11 is claimed to be unparalleled in compact devices.
Powerful drive force and low mass enable the STB11 to accelerate light loads to 25g. The STB11 range includes strokes of up to 372mm, 46-92N peak force, and 3.1-5.2m/s maximum velocity. Users can optimise servo position control by matching STB11 linear motors to Copley's Accelnet digital controllers. Accelnet controllers provide powerful standalone and multi-axis control choices; networking options include CANopen, Ethercat, Macro and DeviceNet.
