Small object does not stick on bed

Discussion in 'Calibration, Help, and Troubleshooting' started by Tetrikus, Mar 27, 2016.

  1. Tetrikus

    Tetrikus Well-Known Member

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    Hi all
    I've some problems with a PLA filament and a smaller object I want to print (about 20 x 10mm). The filament does not really stick to the bed and at layer 20 or so, the object does slide away and the print cannot be used (of course).

    IMG_0322.jpg IMG_0321.jpg

    The filament says:
    Hotend: 180-210°
    Bed: 20-60°

    I've read, that the bed should be hotter when the material does not stick to the bed, therefore I tried with 195° hotend and the bed between 60° and 80°. I also tried to have 80° at the first 5 layers and after that 60°. Still the same issues. Any ideas what I could try in such a case?

    The filament is a Swiss brand, this is it. I tried others from the same brand and did not have this issue.

     
    #1 Tetrikus, Mar 27, 2016
    Last edited: Mar 27, 2016
  2. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    Maybe a silly question, but did you use the Uhu stick ore some other adhesive? Usually PLA won't stick to bare glass.
     
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  3. Tetrikus

    Tetrikus Well-Known Member

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    Now its official, that I'm a complete noob in regards of 3D-Printing. :) No, I did not use Uhu stick or something else. But honestly, the example PLA and two other PLAs I printed sticked very tight on the glass and it wasn't easy to remove it from the glass after printing. So, it looks like PLA is not equal to PLA. :) Thanks for the hint, though, I'll have a look where I find this Bird-Thing. :)
     
  4. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    You are right. Some kinds of PLA are more equal than others :)
     
  5. mike01hu

    mike01hu Well-Known Member

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    If you have some PVA wood glue, then a mix of that with water, about 5:1 or even 8:1 i.e. 5 or 8 parts of water to one of PVA, lightly wiped over the bed with a piece of kitchen roll will also improve adhesion. The bed can be cleaned with ethyl alcohol (methylated spirit) to remove the coating if necessary.
     
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  6. Tetrikus

    Tetrikus Well-Known Member

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    Thanks, I'll try this. :)
     
  7. Mike Kelly

    Mike Kelly Volunteer

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    Looking at the picture you'll want to reduce your Z offset a bit to get closer to the bed on the first layer.

    Smaller is harder for FDM printers
     
  8. Spoon Unit

    Spoon Unit Well-Known Member

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    I had a little (well OK a lot) of trouble trying to print a large patch of small footprint items. In the end I decided to use a raft. Getting them off the raft is a slight pain, and did cause a little damage to the print surface (white marks where the tearing occurred). I decided to try applying a little heat to those marks and that really removed the white bits, leaving perfect-looking prints. In the end I was able to print a batch of 20 with 100% success. The other part, which the small footprint screws into, was just enough to give a pretty decent success rate without a footprint, yielding 19/20 successes. I never did pluck up the courage to go for a full bed of those yet (which would be 150 items).
     
  9. Tetrikus

    Tetrikus Well-Known Member

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    Thank you @mike01hu , this tip was gold, as it looks so far. I will of course order some more convenient stuff, but this was the perfect easter rescue. :D
     
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  10. Spoon Unit

    Spoon Unit Well-Known Member

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    @Tetrikus, could you clarify which part of the tip you followed? Did you mix at 5:1 or 8:1? Also how small is the footprint? What are the dimensions on the base layer?
     
  11. Tetrikus

    Tetrikus Well-Known Member

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    I mixed about 8:1, but not very exact. The base layer of this mentioned object was about 3cm2, but I also had the issue when printing objects with much more surface (about 40cm2). As an emergency plan it was just great.
     
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  12. mike01hu

    mike01hu Well-Known Member

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    I tend to use about 5:1 but it's not critical. I just keep a bottle made up for shake, squirt and wipe.
     
  13. Spoon Unit

    Spoon Unit Well-Known Member

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    I think the items I was printing had a circular base with diameter 6mm. I might give diluted PVA a try to see if that is better than UHU, which I presume is, overall, a similar compound.
     

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