Mechanical limit switches (limit switch)

Mechanical limit switch  (limit switch) is manufactured already in a housing or in the form of a mounting plate with terminals for connecting wires. The limit switches already have all necessary mounting holes for their installation on the device.

The main, and perhaps the only, purpose of mechanical limit switches is to determine the extreme points of movement of the working bodies of 3D-printers and any other CNC device.

The principle of operation of the limit switch

When the axis of the 3D printer moves and reaches an extreme value, the carriage or work table presses the foot of the limit switch, closing its electrical circuit. The signal from the mechanical switch goes to a microcontroller, which in turn sends a "Stop" command to the desired stepper motor.

Important! The mechanical switch can be used not only as a sensor to determine the boundary of the working space of the 3D printer. It can also be used to determine the origin of coordinates in the X, Y, Z axes (the "Home" command on many models of CNC machines).

Mechanical limit switches

. Almost all 3D printer models use the simplest, yet most reliable mechanical contact limit switches. But recently, on more modern models of 3D printers manufacturers began to install and contactless optical switches. In these switches, the main working organs are an LED and a photoresistor. As a rule, these devices operate in the infrared range invisible to humans. But despite this, all mechanical limit switches are made compact, while having durable housings and reliable mounting points.

How to choose a limit switch?

To choose the right limit switch, it should be remembered that mechanical contact models operate with characteristic clicks, which in regular operation can cause some inconvenience.

Optical switches work silently and more accurately, but they cost a little more. The main disadvantage of the optical limit switch is the presence of false triggers when sunlight hits the sensor.


Before you buy a limit switch for your device you need to decide on the following parameters:

• Speed of triggering;
• Type - mechanical and optical;
• Operating voltage;
• Dimensions and weight;

A wide range of components for 3D printers and other CNC devices.