Understanding Linear Steppers

Looking for a solution to achieve a linear motion in a compact package size? Portescap Digital Linear Actuators (DLA) take full advantage of the cost efficient design from can stack stepper motors with a built-in lead screw. Thus the DLA technology will help achieve space and cost savings over conventional motion solutions through the elimination of mechanical components such as gears, belts and separate threaded shafts or screws.

To directly convert rotary motion into linear motion, the digital linear actuator stepper motor is a can stack stepper motor with a built-in leadscrew. The actuator uses the basic can stack stepper motor design with either a 7.5 or 15 degree step angle. The rotor magnet sits on a thermoplastic nut captured between two ball bearings secured in the end caps. The linear stepper motor can be captive or non captive, depending on the level of integration required.

Non-Captive Stepper Linear Actuator
The resultant motion is linear but the screw also rotates, and anti-rotation is within the customer’s application.

Captive Stepper Linear Actuator
The shaft is made of two pieces:

  • The rear section is a leadscrew and rotates through the nut.
  • The front section is a grooved shaft. It engages with a “butterfly” plastic end cap and acts as an anti-rotation

The resultant motion is a pure linear motion.

As the step error is non-cumulative, high accuracies are achieved across long or short travel distances, meaning costly positional feedback devices such as encoders can be eliminated. Motors can be operated in single step, half step or micro stepping modes leading to improved resolution and quieter operation.

DLA products are the perfect fit for applications requiring linear motion in a compact package size. Our team of design engineers can customize to exceed your motion performance specifications, simplify your design and develop a “plug and play” integrated actuation system for your machine. For this reason, Portescap linear stepper actuator is often chosen by many of today’s leading device manufacturers:

  • Medical (syringe pump, pipettes, analyzers, lab instruments)
  • Stage lighting
  • Security and access (door locks)
  • HVAC valves
  • Industrial automation (adjustment mechanism)
  • Telecommunication (antenna positioning)
  • Cost-efficient can stack design
  • High linear power vs. package size ratio
  • Brushless construction for long life
  • Easy open loop control eliminating the need of a position sensor
  • Digitally controlled, easy to control with microprocessor
  • Fast, powerful and precise positioning

Standard Features

  • Reversible motion
  • Captive or non-captive
  • Unipolar or bipolar design
  • Ball bearings
  • 5V or 12V coils
  • Frame size from 20 mm up to 57 mm
  • 7.5° or 15° step angle
  • Linear travel per step from 0.0005" (0.0127 mm) up to 0.004" (0.1016 mm)
  • Linear pull out force from 8.3N (30 oz) up to 124.6N (448 oz)


  • Coil modification (resistance and inductance)
  • Magnet types to yield higher linear force or increase/reduce detent torque
  • Custom lead screw length
  • Custom lead screw tip (imperial / metric)
  • Special mounting flange


Captive DLA

Non-captive DLA