Voice Coils

Iris short-stroke linear actuators have low stiffness and high bandwidth

Short-stroke linear actuators are often called voice coil motors because the same technology is used to drive loudspeakers. Now, they provide high bandwidth movement for applications like semiconductor manufacturing and inspection, and active vibration isolation. Our ironless design uses a stationary array of magnets, normally two, to form the magnetic yoke on either side of a movable coil unit that drives the load.

The Iris short-stroke linear actuators have low stiffness and high bandwidth. Actual figures will depend on the driver unit, and Iris meets the strictest application needs when used with our Apogee/Kepler series of 200 kHz PWM drives. Four models exert a continuous force of up to 250 N and a peak force of up to 1100 N in a motor height of only around 70 mm.

The rectangular actuators are for short-stroke applications requiring a relatively large displacement in three directions. The stroke for the Iris is  ±5 mm in the X direction, with the freedom to move in Y and Z directions without affecting the force generated due to the long coil design.

Negligible attraction force makes installation easier because there’s no magnetic force when the power is off. The motor constant – a key figure of merit for motors – is up to 770 N²/W. There is no contact between the coil and the magnet yoke, so no friction or wear. The coil mass is low while capable of producing high force giving a fast response. 

Thermal resistance is low, and the coil casing is optimized for heat transfer. The PT1000 provides temperature sensing for the medium and large motors, and the magnets of the yoke are shorter than the back irons to give magnetic shielding. The coil units are equipped with connectors and are IP10-rated for dust protection.

They work seamlessly with our servo drives and motion controllers, and our Prodrive Motion Platform (PMP) control software.

Typical applications include:

• Semiconductor manufacturing and inspection.
• Active vibration isolation to cancel out any vibration picked up by sensors coming from in- and outside the system.