Fixing the Z axis limit switch

Fixing the Z axis limit switch


When to fix the Z axis limit switch

If your printer moves unexpectedly when starting a print, or an axis keeps trying to move even though its at its limit, there may be a problem with one of the axis limit switches. While this is a rare occurrence, troubleshooting this issue is very simple.

What do I need?

- 1.5mm hex key (included in your printers maintenance kit).

Step 1 - Access the maintenance console

- Log in to BuildBee with an account that has the right to maintain printers.
- Access your printer list from the top right hand corner of the screen.



- Select the 'MAINTENANCE' button next to the printer that has the issue.



- Under the 'CONTROL' tab, make sure your printer is in the home position by selecting the 'HOME' button:



Step 2 - Check the status of the limit switch

- Select the 'MAINTENANCE' tab to access the GCODE terminal.




- In the GCODE terminal, type M119 and press enter. The terminal will return a message telling you whether each limit switch was registered as 'TRIGGERED' or 'open'. In the home position, all switches should report 'TRIGGERED' as their status. If a switch shows up as 'open' even though it was physically pressed in, that switch is not working correctly.




 

- Once you have confirmed that the switch is not working, you can begin to look for what is causing the problem. The following steps will help you identify where the issue lies:


How to check the Z axis limit switch

Step 1 - Check for damage to the switch

- Inspect the switch itself. is the outer casing of the switch damaged? Do the wires appear to be free of damage and connected to the switch properly?





- A damaged switch will no longer trigger properly and will need to be replaced.

Step 2 - Check for plastic stuck in the switch

- Is there a thin piece of plastic stopping the switch from being pressed or being released?


- Carefully remove the piece of plastic with your fingernail or a pair of tweezers.

Step 3 - Inspect the wires

- Look for signs of damage along the wire itself.

- There is an extra connection between the Z limit switch and the extruder wiring harness to inspect. Make sure the plugs are connected properly.

wire_plug.png

- At the base of the printer where the wiring harness plugs in, inspect the top two wires of the right hand plug. Make sure these wires aren't loose or damaged and are seated properly in the plug.

If you found a fault and were able to fix it, you can run the M119 command in the GCODE terminal to confirm that the switch in question is now working. If the switch now works, there is no need to continue onto the next section.

If you are unable to get the limit switch working, please raise a support request


Replacing the Z axis limit switch

Step 1 - Remove the broken switch

- While the nozzle is not hot, turn your printer off and prop up the X axis (extruder arm). A filament box works well for this. Make sure the limit switch on the extruder is accessible.
- With a 1.5mm hex key, take out the small screws that attach the limit switch to the extruder. Put them in a safe place.
- Unravel the black wire binding to access the extruder wires. Put this aside for now.
- Unplug the limit switch.

Step 2 - Fit the new switch

- Fit the new switch in place with the screws you took out. Make sure the screws are screwed in from the back. Use the pictures above as a guide
- Plug the new switch in (it only fits one way). Make sure to guide the wires in front of the heat tube.
- Wrap the black wire binding back around the extruder wires.
- Return the extruder back to the home position.

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