Printhead banging to the back

Discussion in 'Calibration, Help, and Troubleshooting' started by Tetrikus, Mar 28, 2016.

  1. Tetrikus

    Tetrikus Well-Known Member

    Joined:
    Mar 17, 2016
    Messages:
    81
    Likes Received:
    12
    Hi there
    I noticed, I have some issues on print start. Had that several times when I forgot to autohome before printing but this time was the first time I was able to catch it on video.

    YouTube: https://youtu.be/wDzKpEXILuc

    It sounds and looks quite painful. It the printer to stupid or do I have a misconfiguration anywhere? What should the behaviour be, when I start a print before autohoming before? And is really the missing autohoming the issue here? This happened several times, and it hurts so much every time. :s
     
  2. Alex9779

    Alex9779 Moderator
    Staff Member

    Joined:
    Sep 4, 2015
    Messages:
    2,405
    Likes Received:
    731
    Hard to say, maybe post the first lines of the gcode you are running? Up until the first layer...
     
  3. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    I've had this a couple of times. You definitely want a G28 at the start of your GCODE to prevent this. The times I had this the most were right at the start when using the e3d-supplied benchy, which doesn't have a G28 at the start. So you print a benchy then the head parks, then you try to print another one and have that issue. Horrible moment, and I know exactly how you feel. This was one of the reason I opened up the hole to give me access to the front LCD kill-switch.
     
  4. Kanedias

    Kanedias Well-Known Member

    Joined:
    Sep 12, 2015
    Messages:
    406
    Likes Received:
    124
    Remember to preheat first though so if you have a gob at the nozzle it doesn't smack into the bed
     
    #4 Kanedias, Mar 28, 2016
    Last edited: Mar 28, 2016
  5. Rob Heinzonly

    Rob Heinzonly Well-Known Member

    Joined:
    Sep 20, 2015
    Messages:
    362
    Likes Received:
    125
    If you didn't do a auto-home and the head is going for the dump bucket, this will happen. The printer doesn't 'know' where the head is without a auto-home, and most probably will crash in the back. It's no misconfiguration, but just something to be aware of when you are moving the head to the dump bucket.
     
  6. R Design

    R Design Well-Known Member

    Joined:
    Oct 7, 2015
    Messages:
    918
    Likes Received:
    183
    This can also occur when using the dial to navigate.

    Basically never assume that Marlin is going to stop!

    Perhaps with RC4 it will be different?
     
  7. Alex9779

    Alex9779 Moderator
    Staff Member

    Joined:
    Sep 4, 2015
    Messages:
    2,405
    Likes Received:
    731
    @R Design RC4 won't help anything here...
    The problem is the cutout for the ooze bucket. For being able to move the head there the Y max has to be 240 as the Y max for printing is only 200.
    In Marlin you can only set X Y and Z max values so for Marlin your volume is 260x240x300 for dual.
    It would be necessary to tell Marlin that your Y max is 200 but between X70-X140 (?) Y max is 240.
    Currently this is not possible and not a planned feature as far as I know...
     
  8. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    If it's a regular thing to have an ooze/dump bucket or some sort, perhaps they should include it. Of course, it could always be coded by E3D for the BB.
     

Share This Page