SMAC Commercializes Innovative High-Torque Robotics Motor with Halbach Magnetics Circuitry and Printed Coils

Using Halbach arrays of Neodymium magnets and printed coils, mechatronics developer SMAC is commercializing its innovative high torque brushless DC motors that it designed for robotics and electronics applications. 

“The HT is a new revolutionary high torque brushless DC motor,” according to Ed Neff, president. “Compared to other brushless motors, it has a flat torque–speed curve meaning that the speed is less influenced when the torque is increased. The secret to that is found in how the magnetic circuit is built. A combination of our patent pending Halbach magnets and printed coil technology achieves the higher torque/amp.” 

SMAC recently introduced the HT35 as the first model in its HT series. Next will be the HT55, a 55-mm model, that is presently in development. 

“These are very powerful little motors,” explains Neff. “The Halbach magnet circuits increase torque more than twice that of conventional types due to their high flux density of over 10K gauss. The magnet assembly is molded as one piece and by printing the coils like in a flex circuit, we are able to make winding configurations not possible with conventional winding methods.” 

One application for which the motor was developed was to make a robotic finger. Peak torque of the HT35-25-24K model, a brushless 12-pole motor pictured above, is 550 mNm with maximum speed of 2700 rpm and having a maximum efficiency of 85%. 

As a company, SMAC specializes in developing and manufacturing advanced electric actuators aimed at replacing traditional technology devices such as pneumatic cylinders, ball screw actuators, and moving magnet type linear motors. Its main markets are electronic assembly, automotive manufacturing, packaging, and more recently biotech, consumer electronics, and semiconductor. 

Moving coil key to the technology 

At the heart of all its actuatorsis a moving coil much like a voice coil actuator. The essential principle is the same as in a permanent magnet loudspeaker. The coil sits in a strong magnetic field and by passing a current through the coil a force is generated in either direction. SMAC applies the same principle to design its linear motors. By controlling current, it can control the force output. 

Key attributes of the actuators include extremely high acceleration and velocity due to lower moving mass compared to the heavier moving-magnet technology used in most linear motors, and very quiet operation which particularly appeals to electronics and automation manufacturers. Force, position, and speed are fully programmable so the actuators can be designed to perform at exceptionally high speeds or very low speeds and with sub-micron accuracy and repeatability. 

SMAC headquarters in California 

SMAC is based in Carlsbad, CA and has other locations across the US as well as at various sites in Europe and Asia.

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