Technical Note:
Maximizing the Lifetime of Your Picomotor™ Actuators

In order to achieve consistent performance and maximize the lifetime of your Picomotor™ actuators, keep the following precautions in mind:

Do not remove the knob or the screw from the housing. The knob is an integral piece of the Picomotor actuator, and its inertia plays an important part in the stick-slip motion of the Picomotor actuator.

If the motor stalls, carefully turn the actuator using the knob. Stalling may occur as the Picomotor actuator ages. By turning the knob and working the screw across the “offending” thread region, the Picomotor actuator can “self heal.”

If the motor hits a stop, turn off the driver as soon as possible. Running the Picomotor actuator against a hard stop will decrease the lifetime but will not cause immediate irreparable damage.

Use a small amount of lubricant between the stainless-steel ball tip and the load surface to prevent wear and the generation of debris in the interface. We recommend Krytox GPL 205 or the low-vapor pressure grease, LVP LCT-42.

Keep the interface between the stainless-steel ball tip and the load surface clean of debris. Even small particles on the order of a micron can make a difference in the repeatability and torsional load of the actuator.

Push against smooth, hard, flat surfaces only, such as the sapphire pads used in New Focus™ mirror mounts and translation stages. Pushing on aluminum or stainless-steel surfaces will wear out the ball tip. If the load surface is too soft, small amounts of material can build up in the interface between the ball tip and load surface resulting in surface roughness which can degrade repeatability.

Do not push against cone or v-shapes, especially in softer materials such as aluminum. When the ball wears against a cone or v-shape in softer materials, particle generation can lead to increased friction and torsional loads. These torsional loads can easily exceed the torsional load limit of 2.5 oz-in (0.018 N•m) thus stalling the motor.

Avoid damage to the screw threads. Do not touch the screw threads with any hard object – even lightly. Through careful control over the screw and nut thread manufacturing process, we can enable high quality performance. To provide the fine resolution, the screw has very fine-pitch threads. If the threads are damaged, this damaged area will produce repeated excessive wear within the fixed motor housing and significantly reduce the lifetime of the motor.

Avoid clamping tightly on the motor’s housing. This can cause increased friction between the rotating inner screw and the fixed exterior housing resulting in slowed motor motion or complete failure. This can also result in damaged screw threads.

Periodically examine the stainless-steel ball tip and the load surface for wear.

Following these guidelines will help minimize any damage to the device or introduction of debris in the nut cavity, which is a primary driver of premature actuator failure. Please feel free to contact us if you have any questions.