Anycubic Kossel Marlin extruder calibration

1. Preparation

1.1. Heat up the nozzle

Start by heating up the nozzle to your printing temperature PLA 190°C, PETG 230°C, ABS/ASA 250°C

1.2. Retract filament

Push the extruder calipers and retract filament from bowden with the other hand

1.3. Bowden removal

Press the bowden coupler and remove the bowden

1.5. Insert filament

Cut the end of filament with pliers and insert it into the extruder

1.6. Mark/align filament

There are two good ways how to do this:
1) Use a marker and draw a start line
2) Aligh end of filament to the bowden coupler

2. Extrude 100 mm

2.1. Marlin FW, Pronterface method

Start by downloading and installing Pronterface: DOWNLOAD
Connect your printer via USB to your PC, choose a port, click on Connect

2.2. Octoprint

If you use Octoprint or Octoprint + Klipper, simply open Octoprint and navigate to Terminal

2.3. Send M83 command

This command is used to override G90 and put the E axis into relative mode independent of the other axes.

Click here for more information

2.4. Send G0 E100 command

G0 / G1 – axis movement
E100 – extrude 100 mm
For deltas you can use both G0 and G1, for cartesian printers use G1

If you use Klipper and you did not modify max_extrude_only_distance to 100 mm or higher, simply send 2x G0 E50

Click here for more information

3. Measure extruded filament

This is the most crucial part.
Measure the lenght multiple times and calculate a median.

4. Calculate new steps/mm – step_distance

4.1. Marlin steps/mm

Marlin uses steps / mm which means that you have to loop up for your actual steps/mm value.

Use a pronterface and send M503 command to retrieve the value.

4.2. Marlin calculate new steps/mm

Now comes the math…
You wanted to extrude 100 mm
But you extruded only 99 mm

This means that you are underextruding and you want to calculate a new and corrected value.

New steps/mm =
Actual steps/mm x (what you wanted to extrude / what you extruded)

For example:
You wanted to extrude 100 mm
But you extruded only 99 mm
Your actual steps/mm value is 120 steps/mm

New steps/mm value = 120 * (100 / 99) = 121.212 steps/mm

4.2. Marlin save new steps/mm

Use a pronterface and send this command:
M92 E[New steps/mm value]

For the previous example:
M92 E121.212

Restart the printer, connect it to Pronterface and check if the value is the same with a M503 command.