Many OEMs and automation-equipment manufacturers are turning to linear motors rather than leadscrews for linear motion. This eliminates all belts, chains, gears, and the need to convert rotary into linear motion. Linear motors also eliminate wear, cogging, and backlash.
To meet the need for a smaller form factor, Copley Controls Corp., Canton, Mass. (www.copleycontrols.com), developed the TT Micro line of linear motors. The motors have a peak force of 45 N, accelerations to 60 m/sec2, speeds to 3 m/sec, and repeatability at the micron level.
The motor consists of two parts, the thrust rod which contains strong permanent magnets, and the forcer, which contains the coil set wound as a three-phase brushless motor. Energizing it with sinusoidal currents creates a highly linear force with excellent velocity and position-control capability. Loads and bearings mount directly on the forcer. The TT Micro motors also work with Copley's Accelnet servoamplifiers which are compatible with the CAN open network protocol. This permits multiaxis amplifier-motor axes to be linked by low-cost serial cable, executing synchronized or independent motion profiles without the need of a motion-control card or chips.