Tuning Extruder Height on TronXY

I have a TronXY RepRap 3D Printer. Not knowing much about it when I built it, one of the largest challenges I faced was getting the perfect distance between the extruder (print head) and the printing bed. The printer uses a sensor to determine accurate height, so you actually have to get both the sensor and the head measured properly. I use this simple procedure to line all of this up and all you need is a digital metric caliper and some business cards.

My business cards are 0.355mm thick and I need 9 of them for this.

For me I used one business card for extruder nozzle height and 8 business cards for sensor height. Yours may be different. You will need to experiment to see what is correct for you.

  1. Using software, move your extruder over your print bed so it is a few mm from the surface.
  2. Disable your stepper motors in case you need to manually make any adjustments by rotating the Z axis stepper motors.
  3. Measure both sides of the Z axis to make sure it is perfectly level. If it is not level, manually twist the stepper motors to ensure both sides match (no matter what the height).
  4. Loosen the screws on the Z axis sensor so it is not damaged as you lower the extruder.
  5. Place a single business card under your extruder nozzle.
  6. Lower your extruder nozzle so it is touching the business card, but not crushing it. There needs to be some friction when you pull/push your business card from under the extruder nozzle, but it should NOT be real tight.
  7. I used 8 business cards under my sensor. Yours may vary. Manually adjust the sensor so it’s bottom lies flat on top of the business cards and tighten the screws.  For me, 8 business cards is 2.875mm. Adjust yours as necessary based on your sensor. Your specific details may be labeled on the sensor.
  8. Auto home your extruder and perform a bed leveling test.
  9. This is key! Start a print of something fairly large and watch the extruder nozzle output. If the nozzle is dragging the filament around corners, your nozzle is too high. Re-tune with 1 less business card under your sensor. If the output is almost invisible -smeared onto the print bed, your nozzle is too close. You could ADD a business card to the stack under the sensor and re-test. What you want is a print where the output is sticking to the surface without moving when the nozzle rounds corners. My headed bed is around 55C, and I print PLA at 200 degrees.

There are probably better / more accurate ways to do this, but This method works well for me and I hope it helps you get through this learning curve faster that it took me. As with anything, practice makes perfect so start printing and adjust as needed. Enjoy!