Linear Motors

Unlike linear systems which are driven by rotary motors, linear motors are not restricted in length of travel.

The stationary magnet assembly can be put together to any length using standard rails. Since the moving coil head can be used for any travel, there is no loss of performance depending on travel.

Spindle systems, on the other hand, have critical limits in speed and inertia increases with the length of travel. Speed limits, high inertia and low rigidity are the main drawbacks of other systems in comparison with linear motors for longer travels. 

Functioning of linear motors

Basically, linear motors function in the same way as rotary motors.  Just imagine an ordinary synchronous motor cut up and developed into a plane.

A linear motor has but two components: a winding pack (primary part) and a carrier on which the magnets are fixed (magnet rail or secondary part). The copper windings carry the total current of a linear motor.

The secondary parts consist of rare-earth-magnets mounted onto a steel girder with alternating polarity. They generate a magnet field vertically to the girder. When a current flows in the copper windings, according to Lorentz' law it generates a force F = I x B that can be used to accelerate the mass.

The primary part is usually fitted to the moving parts of the machine. The primary parts are fitted to the static part of the machine. 
  The linear drive permits direct and vibration-free power input into the machine slide with highest speed and path accuracy. Developed for highest speeds and dynamic acceleration, linear motors when used on pattern surfaces with many changes of direction achieve an increase in area processing of at least 30 % and up to 100 %. In the end it is not the quick traverse achieved that matters here (though very impressive) but the enormous axis acceleration of 10 m/sec².

Modern control technology makes these drives controllable and thanks to the function Safety Integrated of the Sinumerik, without which we consider the use of linear motors to be irresponsible, these drives are also safe. 

linear motorsThey are used successfully and without any problems in GEISS trimming machines since 1998. More than 60 machines have meanwhile been equipped with this advanced drive technology. The basic concept of GEISS trimming machines – portal construction with stationary machine table – proves to be ideal for the use of these drives. The economic benefit for the user is quite obvious: Cycle times can often be cut in half. Maintenance costs are drastically reduced. It is beginning to show already today that the life of such a plant by far exceeds that of a plant with conventional drives.     
linear motors

The advantages at a glance:

  • highest dynamics and highest traverse speed, 
  • extreme precision in the contour to be processed,
  • high self-acceleration,
  • simple mounting,
  • nearly maintenance-free,
  • short cycle times for high productivity.


  • trimming of vacuum formed plastic parts,
  • model making,
  • ultrasonic cutting of materials that cannot be trimmed.

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