Got to love the benefits of a large bed

Discussion in 'BigBox General Chat' started by Spoon Unit, Aug 31, 2016.

  1. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
  2. Sarah Nicholson

    Sarah Nicholson Well-Known Member

    Joined:
    Dec 20, 2015
    Messages:
    319
    Likes Received:
    114
    I'll bite.. what are they?
     
    Alex Stevenson likes this.
  3. Christian Riesen

    Christian Riesen Active Member

    Joined:
    Aug 31, 2016
    Messages:
    37
    Likes Received:
    29
  4. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    Yep. I have a feeling my bed adhesion isn't going to be good enough though. I can see a couple of parts beginning to bend. First layer looked just fine though...

    2016-08-31 13.01.26.jpg
     
  5. Sarah Nicholson

    Sarah Nicholson Well-Known Member

    Joined:
    Dec 20, 2015
    Messages:
    319
    Likes Received:
    114
    That's pretty cool, hope it turns out OK.:)
     
  6. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    So far, I have about 5 parts that will be non-viable. 3 have been ripped off the bed and it'll be interesting to see how it copes with the spaces. I'll post an image of the build plate once it's done. Note to self: If you're going to set this much stuff to print in one go, a clean bed and fresh adhesive would be good (or maybe that PEI Alu build plate).
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    Well, I did lose a few pieces. The total print was 84 parts and I think I lose around 7 parts. I suspect I've counted something inaccurately, but nevertheless, I have more than enough track stands to be going on with.

    2016-08-31 18.24.51.jpg 2016-08-31 18.35.29.jpg
    2016-08-31 20.22.05.jpg
     
    Sarah Nicholson likes this.
  8. Christian Riesen

    Christian Riesen Active Member

    Joined:
    Aug 31, 2016
    Messages:
    37
    Likes Received:
    29
    In my experience, printing less parts usually ends up in shorter print times and less waste. I have been using only PLA but even then I had warping a lot when printing two semi large parts together. Just doing them single would have been better and turns out also shorter. The travel time between parts adds up crazy.
     
  9. R Design

    R Design Well-Known Member

    Joined:
    Oct 7, 2015
    Messages:
    918
    Likes Received:
    183
    Was there any pattern to the parts that came unstuck? (eg near the edge?)
     
  10. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    Well, many pieces had an external and internal edge. I'm sure you're going with uneven heating, and I think that's at least partly the issue. One way to counter that would seem to be to warm high enough that the external edge has the heat you want. Another observation is that these were thin pieces with no bridge until the final three layers, so I could probably have dropped all cooling until that final layer to reduce the impact of a gale force blowing again a relatively small and thin piece of plastic. I just abandoned a print of 11 corner pieces as I had a number of those pulling away. I'll probably swap the bed for a clean one in the morning and re-UHU. I'll then adjust S3D so the (50%) gale doesn't blow until we reach the first bridge.

    Once you have a piece came free it can become murderous for the rest of the pieces, partly because the second print head and can give the extra tug required to pull things apart.
     
  11. R Design

    R Design Well-Known Member

    Joined:
    Oct 7, 2015
    Messages:
    918
    Likes Received:
    183
    I'll bet if someone does a thermal photo of the Aluminium bed that the corners are not 10C cooler as on the PCB backed glass one. (It's a great conductor.)
     
  12. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    I didn't realise it was 10; that's a lot, and certainly enough to cause issues if you don't take account of it. Perhaps this could be a reason to actually allow the heated bed to sag a little in the center, and use supports around the edges.
     
  13. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    At first glance, the changes to fan speed and bed cooling appear to have been sufficient. The first overhang in the next set of models appears on layer 17 (at 0.3 height), so I'm keeping the fan off until then. I'll also maintain the bed temp at 75 throughout. So far, the print is going well with zero lifting even at the edges.
     
  14. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    That printed just fine then:

    2016-09-01 10.54.09.jpg
    2016-09-01 11.00.25.jpg
     
    Colin, mike01hu and gonzalo like this.
  15. Christian Riesen

    Christian Riesen Active Member

    Joined:
    Aug 31, 2016
    Messages:
    37
    Likes Received:
    29
    These look great @Spoon Unit

    Did you have any warping on them?
     
  16. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    zero warping on those ... or the next set of 12 straights
     
  17. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    Nice large part. Again zero warping. Painful however that the bearing that's supposed to fit in the center drops straight through. I think older designs are just not setup for accurate printers. 2016-09-02 07.22.47.jpg
     
  18. Old_Tafr

    Old_Tafr Well-Known Member

    Joined:
    Mar 7, 2016
    Messages:
    560
    Likes Received:
    75
    Loctite do some great stuff for locking bearings in place....... I will dig it out to let you know what it's called, it's a nice green colour too !!
     
  19. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    I redesigned it so the bearing would be a nice tight fit. Much better. At the same time, I drafted the holes so that the ball will sit nicely in the holes without any need to have the whole contraption angled.
     

Share This Page