Your Me2 is factory calibrated and tested when it arrives. You DO NOT need to run through this calibration process unless your prints are failing due to some change that has occurred in transit. Contact email@example.com for further advice if you are suffering out-of-the-box failures.
The Z-Offset defines the actual height difference between the Z-height probe (the limit switch on the extruder head) and the extruder nozzle. It’s an important number that can be the difference between a perfect print and a squiggly pile of plastic spaghetti.
You shouldn’t need to calibrate your Z-Offset often, only when a change to the extruder has occurred. Please note that a new Me2 fresh out of the box is already calibrated. Still, you may need to tweak your offset from time to time due to wear, transport or part replacement.
Check your current Z-Offset
- Start MatterControl and connect your Me2.
- Show the Terminal ("View menu" > "Terminal"). If filter output and auto uppercase aren’t checked, enable them now (for readability).
- Type in M851 and hit enter. The machine will report back the current Z-Offset in machine memory. Take note of this number and close the terminal window.
- Go to the Settings tab in MatterControl and enable advanced settings.
- Go to the "Printer" > "Print Area" sub-tab and look at the Z-Offset value.
- Your current Z-Offset is the combined total of the values from steps 3 and 5.
Ideally, if you have a value set in the machine memory then your software Z-Offset should be set to 0. You can use the software offset for tweaking, but the best habit to get into is to program it into memory every time.
Measuring your new Z-Offset (“The Paper Test”)
For this process you’ll need a standard piece of 80 GSM printer paper or similar thickness (around 0.1mm).
- With the tip cold, and the Me2 plugged in and turned on, home all your printer axes on the controls tab.
- In the bottom of the controls tab there is a macro labelled 'Z Offset’* - click the button and let it run.
- With the extruder nozzle now positioned over the home corner (the back left of the build tray), set the control step size to 1mm and use the Z+/Z- controls to bring the head down until it’s almost (but not actually) touching the tray.
- Put your piece of paper under the nozzle so it is lying flat on the print bed. If you can’t fit the paper under the nozzle, click Z+ once to bring the head up so you can fit the paper underneath.
- Set the control step size to 0.1mm. Click the Z- button to bring the head down 0.1mm while moving the paper around. Repeat clicking the Z- button until you feel the nozzle pinch the paper.
- Press the Z+ button once - you should be able to move the paper around again.
- Set the control step size to 0.02mm. Using the same action as in step 5, move the paper around while clicking Z- until you just feel the paper pinch.
- You should now be able to feel slight pressure when moving the paper around, but should be able to pull the paper out from under the nozzle and with only light pressure push the edge of the paper back under the nozzle. If the paper is completely pinched or you can’t push it back in, you’re too low - go up and try again. Your nozzle should now be about 0.1mm off the deck - perfect print height!
- In MatterControl, take note of the current Z coordinate value underneath the movement controls.
To get your new Z-Offset value, add the Z height value you’ve just measured to the current Z-Offset value from the machine memory.
Using M851 we find the current Z-Offset is 6.4
Using the paper test the printer thinks the ideal print height is -0.3.
Our existing Z-Offset was too high!
Our new calibrated Z-Offset will be 6.4 + (-0.3) = 6.1
Setting your new Z-Offset
- Bring up the terminal again ("View Menu" > "Terminal")
- Type in
M851 Z###where ### is the new Z-Offset value you calculated with the paper test. Hit enter.
- The terminal will report the new Z-Offset value back to you. This is now in machine memory, but not stored permanently.
- To permanently store the new value, type
M500and hit enter. The machine will take a couple of seconds to write the new value to the EEPROM.
- To confirm that it’s all worked, type
M501and hit enter. This will load all settings from EEPROM and write them out line by line; at the bottom of the response you should see the new M851 value.
That’s it! You’re calibrated! Make sure the Z-Offset in your slicing software is set to 0 and you’re good to go.
Software Only Z-Offset
If you are using the software only method, your machine Z-Offset is always 0 - therefore the whole Z value you determined from the paper test is the new Z-Offset calibration that you’re after.
Enter your new Z-Offset value in the Z-Offset box of the "Settings" > "Printer" > "Print Area" subtab in Mattercontrol and you’re all set.
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