Lines Method (DEPRECATED)

:dizzy: This page is compatible with Klipper and Marlin.

  • :warning: This has been deprecated in favor of my new pressure advance tuning tool! See :page_facing_up: here.

  • :warning: The contents of this page may be out of date!

Table of contents

Steps

  1. Visit the :page_facing_up: pressure advance calibration site.

  2. Fill out the parameters specific to your setup (printer name, bed size, retraction, etc.)

  3. Modify the Start G-code section.

    :warning: Exercise caution here. As mentioned previously, you can damage your printer if you don’t set up the start g-code correctly, for example forgetting QUAD_GANTRY_LEVEL or PRINT_START (if used).

    • This is where you will set your temperatures (M109/M190).
    • Copy over your slicer’s start g-code (from your printer profile) and paste it beneath the M109/M190.
      • You can usually replace the default gcode beneath the M109/M190 with your own start g-code*, but use your best judgment. The defaults are there as safeguards.
      • Klipper
        • Stock PRINT_START/START_PRINT macros usually contain all the necessary start gcode (minus the temperatures), but please double check.
          • For Vorons with the stock PRINT_START macro, this is all you need:
          • If you are :page_facing_up: passing variables to PRINT_START, remember to append them here. Example: PRINT_START HOTEND=240 BED=110
            • Your variable naming may be different, e.g. EXTRUDER=X instead of HOTEND=X.
            • You can then comment out the separate heating g-codes.
      • Remove the M112. This is an emergency stop / reading comprehension check to ensure you have reviewed the start gcode.
      • * If the start g-code from your slicer has any slicer variables (for example [first_layer_bed_temperature]), make sure to replace them with appropriate values.

  4. Fill out the tuning parameters. Many can be left at defaults, but here are some specific settings that I recommend:

    • Printer
      • Layer Height: 0.2mm*
        • *Or the primary layer height that you intend to print at. <0.2mm can make first layer difficult, however.
        • *On textured beds, you may want to try 0.25mm to verify if your results are reading high (>0.06 PA on direct drive)
    • Speed
      • Slow Printing Speed: Your square_corner_velocity From your printer.cfg. Default is 5.
        • For Marlin, use your typical jerk value.
      • Fast Printing Speed: Your perimeter speed
        • If your internal/external perimeter speeds are different, use the faster of the two.
        • :warning: See :page_facing_up: this table to ensure that you are not exceeding the maximum flow rate of your hotend.
          • The line widths refer to the “nozzle line ratio” option.
            • Default is 1.2 (120%).
        • *If your perimeter speeds are particularly slow, it may be hard to read the results. You may need to use a higher speed here in that case.
      • Acceleration: Your perimeter acceleration
    • Pattern
      • Starting Value for PA: 0
      • Ending Value for PA:
        • Direct Drive: 0.1
        • Bowden: 1.5*
      • PA Stepping:
        • Direct Drive: 0.005
        • Bowden: 0.05*
      • Test Line Spacing:
        • Voron 0 (120mm bed): 4
        • Default: 5
      • Print Anchor Frame: Checked
    • Advanced
      • Nozzle Line Ratio: 1.2
      • Prime Nozzle: Unchecked
      • Dwell Time: 0

    * These bowden values cover a wide range of PA (0-1.5), because each bowden setup can vary widely. Once you narrow down a general range to work in, you may want to run the test again with a narrower range of PA values.

  5. Generate and download the g-code file.

  6. Print it, and inspect the results.

    • In the below example, I would choose about 0.055.

      Result

    • This is a great visual representation of what I mentioned earlier: that pressure advance is rarely perfect.
    • Always choose the lower value if you are not entirely sure.
    • Sometimes the best acceleration and decelerations values will not be on the same line. In this case, you should pick a midpoint between both.
      • If they are more than a line or two apart, see the next section.

  7. See :page_facing_up: Saving Your Value.

Anomalies / Issues

This PA test also serves as a nice extruder stress test, and it’s a great visual indicator for extrusion issues. It ensures that your extruder/hotend can handle your requested speeds, PA, and accelerations.

  • If your best accel/decel PA values are more than a line or two apart:
    • You may have too much :page_facing_up: backlash in your extruder. Pressure advance uses a reverse extruder move during decelerations. Excessive backlash causes some of that reverse move to be lost.
    • See :page_facing_up: here for more information on the effects of backlash/gear tension.
    • You still want a tiny amount of backlash (when filament is loaded) to ensure your extruder gears aren’t over tensioned. Essentially as little as you can manage.
    • This is not adjustable on some extruders like the Orbiter (doesn’t have the same backlash issues anyway in my experience!)
  • If your PA numbers are unusually high:
    • This may indicate a partial nozzle clog or that your hotend temperature is too low. More back pressure means more pressure advance.
  • If the middle (fast) section is not printing, or is only partially printing:
    • Your printer is having issues extruding at faster speeds. You may be outrunning your hotend, have your temperature too low / incorrect thermistor type in your config, have your extruder motor currents incorrect, have a partial clog, or have an extruder assembly issue. See :page_facing_up: here for more in-depth troubleshooting.
    • If this only happens above your ideal PA value, it’s not an issue.