Live-Z Calibration


These notes are based on my experiences with the Prusa i3 Mk3 printer. If you are using a different printer, please verify the hardware details are same. These pages may be a bit rough as I revise them and add new material. Please check back regularly for updates.

Getting the proper spacing between the nozzle and print bed is critical for a successful 1st layer. A successful first layer is critical for a successful print. Unfortunately, the process can be a bit difficult to master when starting out. Prusa provides a “Live-Z” calibration option as an on-board menu selection. While this procedure works, it can be a bit difficult to interpret the results, particularly for newcomers. Jeff Jordan developed a much-improved procedure that is detailed in the “life-adjust - my way” thread on the Prusa support forum. I recommend reading through that thread and downloading the sample gcode files when starting out.

Alternate Live-Z calibration models based on Jeff Jordan’s “Life Adjust” procedure

As you move on, particularly when you start experimenting with new materials and nozzle sizes, you may need to re-calibrate your Live-Z setting based on new filament or nozzle settings. Here are the prints that I’ve created to calibrate my Live-Z setting.

  1. A basic 75x75x0.20mm single layer square with rectilinear infill. This basically replicates Jeff Jordan’s “life-adjust” print for different filaments and nozzle sizes. The square is big enough to easily see what’s going on and the infill pattern lets me gauge the impact of one layer on adjacent layers. I want this to print evenly across the entire print with no gaps or stringing.
  2. A large 210x205x0.20mm single layer rectangle that fills the bed with concentric infill. Joan.t on the Prusa forums pointed me to this method to quickly verify that the layer is consistent over the whole bed. There’s no need to print the entire thing, just a few loops around the edge of the print surface to verify everything is even and adhereing well.
  3. A 20mm hollow cube printed in vase mode with 1 perimeter, 0 top layers and 0 infill. The perimeter extrusion width is set to exactly the nozzle size, so I can measure the overall dimensions and wall thickness to get a sense for how well I’m calibrated. This isn’t a first layer calibration print so much as an overall calibration check before moving on to more complex prints.

If you’ve got your Live-Z adjusted properly, you should be able to drag a finger across any of the lines without it coming loose.

Pre-generated Live-Z calibration prints for different nozzle sizes and materials

Here are some 1st layer calibration prints pre-generated as gcode for PLA for various nozzle sizes:

Here are some 1st layer calibration prints pre-generated as gcode for PETG for various nozzle sizes:

STLs for Live-Z calibration and initial testing

Here are the STLS for the 75x75, 210x205mm and 20mm cube prints:

I also like to print some test parts to make sure everything is working well:

  1. A 20mm puzzle part of my own design to test fit and bridging in a short (10-15m, depending on settings) print. These should stack easily with a bit of cleanup. An M5 bolt should fit cleanly through the hole. Print with support to test ease of removal, or without to get a sense for bridging. If I can print this with a new filament or settings and fit it with others, I know I’ve got the basics working.
20mm puzzle part

Fig. 20 20mm puzzle part test print

  1. Stoempie’s complex 1st layer test also at 0.20mm single layer. If I can print this without problems, I know I’ve got my Live-Z and 1st layer down.
  2. Dezign’s Cali Cat as an overall test that prints much more quickly than the ubiquitous Benchy.

It’s worth spending some time to get familiar with this process and mastering the adjustments. You won’t need to re-calibrate frequently, but it is recommended when switching nozzles or making other hardware adjustments.

See also

Contact and feedback

You can find me on the Prusa forums or Reddit where I lurk in many of the 3D printing-related subreddits.

Last updated on Mar 18, 2019