How to choose servo motors and drives

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Revision as of 13:13, 12 March 2014 by Tero K (Talk | contribs) (Choosing linear guides)


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Choosing suitable servo components for a linear motion machine is straightforward process. This article gives a method for choosing suitable servo motors and drives for a machine with linear axis, such as CNC, 3D printing or pick'n'place systems.

A typical lead screw driven linear axis comprising linear guides, lead screw and a motor. To drive this, a motor driver and power supply is needed.

Defining goals

The first step is to define goals of the system. Find numbers to the following questions:

  1. How much is the required linear force?
  2. How much is the maximum desired speed?
  3. What is the required accuracy (resolution, precision, repeatability)?
  4. What is the required stiffness / nature of mechanical load (stationary/vibrating)?

Choosing electromechanical parts

Choosing linear guides

Selection of linear guides have different choices to match desired speed range, stiffness, precision and cost. The following table summarizes most common choices with pros and cons:

Type Cost Precision Stiffness Speed capability
Round linear bearing (sliding) Low Low Low/moderate Medium/high
Round linear bearing (ball) Low/medium Medium Medium (Supported only at end points) Medium
Track linear guide Medium/high High High (Supported from whole length) Medium
Dovetail Low/medium Medium/high Medium/High Low
Roller Low/medium Medium Medium High

Choosing lead screw

Choosing motor

Choosing motor drive


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