Marlin fw 1.1.0-RC6 Z-Offset? (Dual)

Discussion in 'Calibration, Help, and Troubleshooting' started by Brian Dowling, May 10, 2016.

  1. Brian Dowling

    Brian Dowling Active Member

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    @Alex9779 - Since I was hitting some of the bugs in RC3 I decided to give your build of RC6 (a069f6)
    a try. After bed leveling, I was able to get a few good prints going with it, so far so good.

    [I know this is bordering on a Marlin question, but we were just talking about this here..]

    One thing I did notice however, when the bed is homing, it does drop to the MIN_Z_HEIGHT_FOR_HOMING and zeros in Z on the bed just fine. But it stays there rather than dropping the bed. e.g. From the original RC3 stock I was getting used to the 4mm offset for Z, which is nice when it heads to purge, etc that it wasn't kissing the glass the whole way (Re: z-axis-bed-offset ).

    Do you know if there is a setting in RC6 I can change to get that behavior back? I can always add it to my print start scripts, etc but it was nice that it was doing it by default before, for SD card printing, different slicers, etc. I guess I'm also seeing this can be a challenge identifying all the changes in Marlin releases without being buried in the code..

    Also, does anyone know if there is docs somewhere on Marlin UI, that steps through the LCD menus, etc and provides deeper insight into what the settings mean? Finding it challenging to find this level of detail.

    Thanks,
    Brian
     
  2. Alex9779

    Alex9779 Moderator
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    No sorry I don't think this is possible. But I will have another look.

    I didn't find something like that yet and I assume it does not exist. You saw my other post about the recently started Marlin Doc page?
     
  3. Miasmictruth

    Miasmictruth Well-Known Member

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    I added a z drop to the gcode script before it goes to doc

    I am not at home but If I can find the script I will post it for you.
     
  4. Miasmictruth

    Miasmictruth Well-Known Member

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    I pulled this script from the .fff on Alex's profile and opened it as a text as I don't have S3D on this computer. Assuming your using S3D

    *******************START SCRIPT*********************
    BigBox Printer Start Script Begin,
    ;relies on M83 (use relative extrusion distances),,

    M117 Preparing,
    M140 S[bed0_temperature] ; set bed temperature,
    T0 ; select extruder 0,
    M104 S[extruder0_temperature] ; set extruder 0 temperature,
    T1 ; select extruder 1,M104 S[extruder1_temperature] ; set extruder 1 temperature,,

    ;home
    T0 ; select extruder 0
    G28

    ;set values
    M218 T1 X35 Y0 ; set extruder 1 offset
    ;M92 E290 ; adjust steps per mm for your filament,,

    ;move to dock,
    T0 ; select extruder 0,
    G1 X70 Y200 F3000 ; move to position in front of dock,
    G1 X70 Y240 F3000 ; move into dock,,

    ;heat bed,M190 S[bed0_temperature] ; wait for bed temperature,,

    ;heat extruder 0,
    T0 ; select extruder 0,
    M109 S[extruder0_temperature] ; set extruder 0 temperature and wait,,

    ;heat extruder 1,
    T1 ; select extruder 1,
    M109 S[extruder1_temperature] ; set extruder 1 temperature and wait,,

    M117 Print starting,,

    ;BigBox Printer Start Script End
    *******************END SCRIPT*********************



    I modified the move to dock section with an extra Z move like this

    *******************************************************
    ;move to dock,
    T0 ; select extruder 0
    G1 Z1 F300 ; move bed down
    G1 X70 Y200 F3000 ; move to position in front of dock
    G1 X70 Y240 F3000 ; move into dock
    ********************************************************
     
  5. Miasmictruth

    Miasmictruth Well-Known Member

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    One thing I haven't fixed as it should not be an issue if your bed is level and your z taught correctly is when it exits the dock, it will move to the starting layer height instead of waiting until the extruder get into position.

    If you are scraping the bed out of the dock you should level the bed. For mesh leveling instead of using paper I look at the light gap between the nozzle and the bed and slowly lower it, watch both nozzles in case the one your not looking at is lower.

    Move the bed up until the sliver of light disappears, you may want to turn off the light and back light the acrylic. Its easier then it sounds once you get the hang of it and its far more accurate then the paper method, or gcode offset should be able to be set to 0 with this method and get a perfect first layer.
     
  6. Brian Dowling

    Brian Dowling Active Member

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    fwiw, for anyone wondering, this is when the change to have G28 stay at 0,0,0 (when mesh enabled) was introduced:
    https://github.com/MarlinFirmware/MarlinDev/issues/162

    So you do need to have print start scripts that lower the bed before docking/warm up unless you want to scrape across the print deck.. I also made mine come out of the dock after warmup before going to Z0 so as not to constantly nick the edge of the glass in the exact same spot if your Z0 is that close, it shouldn't be, but with bed leveling as it is, never know.
     
    #6 Brian Dowling, May 14, 2016
    Last edited: May 14, 2016

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