Linear motors as direct drives replace more and more conventional screw or belt drives due to their considerable increased performance along linear axis.

Elasticity, backlash, and friction are eliminated while bandwidth, overall precision and resolution are drastically enhanced.

The advantages of linear motors

• high dynamics
- high acceleration capacity
- high final velocity
- excellent static and dynamic load stiffness

• precise positioning
- without backlash
- smooth motion
- tracking with very small error counts during movement

• compact design
• easy mounting in guiding systems
• contactfree operation without wear and friction
• high reliability and a long life time

Application fields

The application of linear motors is recommended if both high dynamics and high accuracy are required.

Typical applications are

• pick and place machines
• bonding machines
• measuring machines
• optical inspection machines
• laser cutting machines
• high speed milling and grinding machines

Design of linear motors

The linear motor comprises of the primary (active winding system) and secondary part (permanent magnet system).

It is usually the primary part which is connected to a movable slider (table) inside a guiding system. When the primary part is subjected to an electric current it develops an electromagnetic force relative to the static secondary part thus resulting in the movement.

A suitable guiding system to maintain an air gap between primary and secondary part is necessary as well as a measuring system along the moving axis to enable the successful operation of the motor.

Depending on the motor type there are differences in the design of the primary and secondary part with respect to their application field.

Courtesy of INA