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Calibration

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github-actions[bot] edited this page Nov 2, 2024 · 44 revisions
  1. Z Offset
  2. GCODE Z Offset
  3. Dock Parking
  4. X/Y Offset
  5. Manual Paper Test

Before you start calibrating you must "break-in" each tool probe. Heat soak your machine and run a couple PROBE_ACCURACY SAMPLES=100 per tool.

Z Offset

NOTE: Tn is the tool on the shuttle, ie T0

  1. Put a tool on the shuttle and run INITIALIZE_TOOLCHANGER
  2. Run G28
  3. Run QUAD_GANTRY_LEVEL
  4. Run G28
  5. Do a Manual Paper Test as normal like a single toolhead head printer and adjust the Z
  6. Copy the offset and save this to z_offset in [tool_probe Tn] of the tool conf file
  7. Repeat from step 1 for all tools (step 2 and step 3 are optional after first tool)
  8. Run FIRMWARE_RESTART

GCODE Z Offset

NOTE: Tn is the tool on the shuttle, ie T1

NOTE: only home or probe with T0 during this calibration

NOTE: gcode_z_offset on Tool 0 is always 0.

  1. Set z_offset for all tools first
  2. Make sure T0 is on the shuttle and run INITIALIZE_TOOLCHANGER
  3. Run G28
  4. QUAD_GANTRY_LEVEL
  5. Run G28
  6. Run G1 Z10 F600
  7. Manually remove current tool and place the next tool in its place on the shuttle
  8. Do a Manual Paper Test as normal like a single toolhead head printer and adjust the Z
  9. Once done run M114 and copy the Z value to gcode_z_offset in [tool Tn] of the tool conf file
  10. Repeat from step 6 for all tools
  11. Run FIRMWARE_RESTART

Dock Parking

NOTE: Set the params_close_y to your highest params_park_y + 30, and set params_safe_y to params_close_y + the thickness of your thickest tool + 10 in the toolchanger.cfg and remove them from the tool config files

NOTE: For params_safe_y you could also just make sure when you have a tool on the shuttle you can move freely behind the dock and not hit any other docked tools and note that y position.

  1. Put a tool on the shuttle and run INITIALIZE_TOOLCHANGER
  2. Run G28 and QUAD_GANTRY_LEVEL
  3. Remove the tool from the shuttle and place it in the dock
  4. Move the gantry as if to pick up the tool, as soon as the light on the optotap pcb changes
  5. Raise Z by 1
  6. Run M114 and record the values to params_park_x, params_park_y and params_park_z in [Tool Tn] of the tool conf file
  7. Run G28
  8. Run SET_TOOL_PARAMETER PARAMETER='params_path_speed' VALUE=300
  9. Run TEST_TOOL_DOCKING RESTORE_AXIS=XYZ
  10. Run RESET_TOOL_PARAMETER PARAMETER='params_path_speed'
  11. Repeat this for all tools
  12. Run FIRMWARE_RESTART

Docking/Undocking

The Moving using config parameters is as such:

Current tool No tool Next tool
safe_y, park_x -> park_z -> close_y -> path close_y -> park_x path -> safe_y -> t_command_restore_axis

X/Y Offset

NOTE: gcode_x_offset and gcode_y_offset on T0 are always 0

Sexball Probe or NozzleAlign

Follow the guide at NozzleAlign

Print STL

Follow the guide at Print STL

Camera or kTAMV

Follow the guide at kTAMV

Nudge

Follow the guide at Nudge

Manual Paper Test

The primary bed calibration mechanism is the "paper test". It involves placing a regular piece of "copy machine paper" between the printer's bed and nozzle, and then commanding the nozzle to different Z heights until one feels a small amount of friction when pushing the paper back and forth.

It is important to understand the "paper test" even if one has an "automatic Z probe". The probe itself often needs to be calibrated to get good results. That probe calibration is done using this "paper test".

In order to perform the paper test, cut a small rectangular piece of paper using a pair of scissors (eg, 5x3 cm). The paper generally has a thickness of around 100 microns (0.100mm). (The exact thickness of the paper isn't crucial.)

The first step of the paper test is to inspect the printer's nozzle and bed. Make sure there is no plastic (or other debris) on the nozzle or bed.

Inspect the nozzle and bed to ensure no plastic is present!

If one always prints on a particular tape or printing surface then one may perform the paper test with that tape/surface in place. However, note that tape itself has a thickness and different tapes (or any other printing surface) will impact Z measurements. Be sure to rerun the paper test to measure each type of surface that is in use.

If there is plastic on the nozzle then heat up the extruder and use a metal tweezers to remove that plastic. Wait for the extruder to fully cool to room temperature before continuing with the paper test. While the nozzle is cooling, use the metal tweezers to remove any plastic that may ooze out.

Always perform the paper test when both nozzle and bed are at room temperature!

When the nozzle is heated, its position (relative to the bed) changes due to thermal expansion. This thermal expansion is typically around a 100 microns, which is about the same thickness as a typical piece of printer paper. The exact amount of thermal expansion isn't crucial, just as the exact thickness of the paper isn't crucial. Start with the assumption that the two are equal (see below for a method of determining the difference between the two distances).

It may seem odd to calibrate the distance at room temperature when the goal is to have a consistent distance when heated. However, if one calibrates when the nozzle is heated, it tends to impart small amounts of molten plastic on to the paper, which changes the amount of friction felt. That makes it harder to get a good calibration. Calibrating while the bed/nozzle is hot also greatly increases the risk of burning oneself. The amount of thermal expansion is stable, so it is easily accounted for later in the calibration process.

Use manual controls to move the tool

Using the webUI (Mainsail, Fluidd, Octoprint) or the LCD Controls, move the tool down and stop just before the bed. Place the paper between the nozzle and bed. It can be useful to fold a corner of the paper so that it is easier to grab. (Try not to push down on the bed when moving the paper back and forth.) Continue to jog the tool down 0.1 at a time. After the nozzle stops moving, push the paper back and forth to check if the nozzle is in contact with the paper and to feel the amount of friction.

If too much friction is found then jog up be smaller increments.

Once you are happy with the results note the Z position (you may also use M114 to get the location).

Taken from Klipper paper test

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