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distortion correction problem

JeromeJerome
in Repetier-Firmware
Hi,

Maybe I am doing something wrong but this is what's happening.

First I use G32 S2 which puts the disitortion map in eeprom if I am right.
When executing bed heigth map 3/4 of it is blue.

By the way what do the colors stand for?

Then when I print the nozzle plunges into the bed.

What am I doing wrong?


Comments

  • RepetierRepetier
    G32 does only rotate, no distortion correction.  That would be G33 if configured.

    You can copy values to clipboard so you get a map of measured values. Colors go from blue over green to red to show min/max values. Your aim is to reduce the difference between max and min value.

    z probe height is a crucial variable for leveling. It tells where z=0 is when z probe is triggered. So if G0 Z0 goes too deep your z probe height is too big, so it calculated bed distance to deep.
  • JeromeJerome
    Thanks,

    If I understand well:
    When the nozzle touches the bed and at the same time the z-probe triggers at 2mm the z-probe height would be 2mm.
    Do I measure with M114 of fysical height?
    So this is a fixed value.

    Max z-probe bed distance is the height where the z-probing starts. is this right?

    Next question.

    I have 2 interchangeable beds.
    I want to be able to measure the distortion and when printing the nozzle to follow that distortion.
    What is the right order in G commands?
    The distortion does not have to be saved in eeprom since I have 2 beds so before very print measure it

    G32 or G33 or G32 +G33?

    Last question, does G28 reset the value of G33?

    Thanks




  • RepetierRepetier
    > When the nozzle touches the bed and at the same time the z-probe triggers at 2mm the z-probe height would be 2mm.
    I think you mean it other way around. If probe triggers and nozzle is 2mm away the z probe length is 2mm. Otherwise you would need nozzle to go through bed to trigger:-)

    M114 is no help since you need to have bed calibrated so it is giving good results, so when you need it to find z probe height is is wrong.

    After changing bed you do the following once to store it in eeprom:
    G32 S2
    G33

    after that simply use G28 to home. As correction stays in eeprom and active until you disable there is no need to calibrate until you do changes requiring this like other bed surface.
  • JeromeJerome
    Thanks  I will try this
  • JeromeJerome
    Ok this is working now.

    Another problem came forward since distortion correction

    The first few layers seem to be over-extruding now untill they reach about 1.4 mm.
    After that print is normal again. 

    How can this be corrected?

    thanks
  • RepetierRepetier
    I don't think it is overextruding. I think you start too close to bed so it lifts extruder a bit and does not need as much filament as you push e.g. printer 0.3 and having 0.1mm first layer height gives you 0.2mm too much extrusion and it takes some height to fix the overextrusion. SO most likely your z probe height should be a bit higher (ok i think higher is right direction, if it gets worse reduce it). And then rerun G32 S2.
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