Jump to content

Print has holes ?


chrisr

Recommended Posts

Posted · Print has holes ?

Hi,

My first print:

Robot

Quick question, what is causing the holes or bubbles?

(The print is with PLA on all the default settings of the Ultimaker2)

I've noticed that the underside of the front belt is very loose and there doesn't appear to be any means to tighten it.

Loose belt

Has anyone any ideas on the holes and also the belt ? :???:

 

  • Link to post
    Share on other sites

    Posted · Print has holes ?

    The holes are caused by "underextrusion" meaning less filament is coming out the nozzle than desired. You can probably hear the extruder stepper skipping backwards - if you watch it on these "bad" layers you can see and hear it skip suddenly backwards about 1/8 turn (but not forwards again).

    The extruder stepper current is low enough so that it will slip backwards rather than grind the filament to dust. This is desirable as grinding to dust would have ruined your print.

    The solution is to either slow down the print or raise the temperature. Raising the temperature of the nozzle makes the PLA flow more like honey instead of toothpaste.

    For PLA I suggest temperatures from 210C to 240C. For speeds - it depends on layer thickness. 35mm/sec is nice and slow and a safe speed.

     

  • Link to post
    Share on other sites

    Posted · Print has holes ?

    Yes, that belt is very loose, and likely to cause problems. Is the top section of that belt very tight, compared to the other belts? I fear that something may have broken in the sliding block to leave that much slack, but maybe it's just not very well positioned on the pulleys.

    Use one of the little allen keys that came with the printer to loosen the grub screw in the front right pulley that the belt goes around. Then rotate the pulley a little to even up the tension between the two halves of the belt, then retighten the pulley.

     

  • Link to post
    Share on other sites

    Posted · Print has holes ?
    illuminarti, on 03 Mar 2014 - 6:24 PM, said:illuminarti, on 03 Mar 2014 - 6:24 PM, said:

    Yes, that belt is very loose, and likely to cause problems. Is the top section of that belt very tight, compared to the other belts? I fear that something may have broken in the sliding block to leave that much slack, but maybe it's just not very well positioned on the pulleys.

    Use one of the little allen keys that came with the printer to loosen the grub screw in the front right pulley that the belt goes around. Then rotate the pulley a little to even up the tension between the two halves of the belt, then retighten the pulley.

     

    The belt has almost an inch or so of play in it and looks perilously close to skipping on the teeth. The top section is about as tight as the other belts are.

    Following a nice chat with HAC, I've actually now rejected the printer and as agreed with them, it's being returned to be swapped out with another Ultimaker2.

    As, I discovered that when the printer sits on a flat surface it will rock on two legs so something somewhere isn't good! The shipping box has signs of impact damage on one corner (which I didn't spot) so it would appear it may have become damaged in transit.

    Shame, these things happen I guess, but I reckon in the meantime I'll just spend more time getting to grips with OpenSCAD, as I have several more projects in mind now! :)

     

  • Link to post
    Share on other sites

    Posted · Print has holes ?
    Skint, on 03 Mar 2014 - 7:54 PM, said:

    Chris, that`s rubbish news, sorry to hear that! Hopefully your next one will be perfect and you`ll be up & running in no time.

     

    Thanks Skint! :)

     

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • Introducing the UltiMaker Factor 4
        We are happy to announce the next evolution in the UltiMaker 3D printer lineup: the UltiMaker Factor 4 industrial-grade 3D printer, designed to take manufacturing to new levels of efficiency and reliability. Factor 4 is an end-to-end 3D printing solution for light industrial applications
          • Thanks
          • Like
        • 3 replies
      • UltiMaker Cura 5.7 stable released
        Cura 5.7 is here and it brings a handy new workflow improvement when using Thingiverse and Cura together, as well as additional capabilities for Method series printers, and a powerful way of sharing print settings using new printer-agnostic project files! Read on to find out about all of these improvements and more. 
         
          • Like
        • 26 replies
    ×
    ×
    • Create New...