[Design Rule Update] Elasto Plastic

Discussion in 'General Discussion' started by 65166_deleted, May 31, 2012.

  1. 65166_deleted
    65166_deleted Member
    Hey guys!

    We've seen a lot of amazing designs for the Elasto Flex material. We've also learned a few more things about the current limits of this material. Here are the learnings and updated rules:

    1) Minimum bounding box: 1.5x1.5x1.5mm AND x+y+z must be greater than or equal to 11 cm
    2) Minimum density: 5%
    3) Multiple Parts per STL: Not acceptable (we need to handle each item with more care for this material, and for that we need to have start up per part)

    Items currently being promoted in the Blog Post and the Home Page for this material will be produced regardless.

    Let me know if you guys have any questions please.

    Thanks,
    Nancy
     
    Last edited: May 31, 2012
  2. stonysmith
    stonysmith Well-Known Member Moderator
    If there are multiple separate, but interlocked parts, is that acceptable? Like chain mail?
     
  3. 65166_deleted
    65166_deleted Member
    When I say multiple parts I mean separate parts. If you have two chain links interlocking that is considered one part.

    Thanks!
     
  4. stop4stuff
    stop4stuff Well-Known Member
    is #1 right, 11cm?
     
  5. neuralfirings
    neuralfirings Member
    Yes, this is the added dimensions of the bounding box.

    So, 1x1x9cm is ok, 4x4x3 cm is too small.
     
  6. stop4stuff
    stop4stuff Well-Known Member
    lol... 1+1+9 = 11, 4+4+3 = 11

    its the units, cm, i'm questioning as the other materials have similar restictions but the minimum is measured in mm.
     
  7. It would be helpful to have an answer to stop4stuff's question: is "11cm" correct, or was it a typo and should be 11mm, not cm, which seems much more reasonable. 11cm is huge.
     
  8. 65166_deleted
    65166_deleted Member
    The 3 dimensions must add up to 11cm (110mm).

    So, 4x4x4cm (x+y+z = 12cm) is ok.
    4x4x2cm (x+y+z = 10cm) is too small.

    This way we get "big enough" items without limiting flat items and pole structures.

    Hope that helps.
     
  9. :eek: I just ordered 16 pieces of 3 different parts that are about 8mm x 8mm x 8mm each and am extremely disappointed to find that you can't print them, as they are critical to my project and I was so happy when I read that you can now do parts in TPE. :cry:

    Why didn't your system flag these as not meeting your design rules? Surely it knows the size of the bounding box from the STL? Is there a way to cancel the order or will that happen automatically later?
     
  10. That part is easy. Just contact the customer service.


    Hey,
    would it be an option to connect your 16 pieces with small sprues ?

    I haven't use BE yet,
    but I think it should be pretty easy to cut the pieces apart and remove the sprues' leftovers with a thin blade.
    (At least that works well for WSF models...)
     
  11. Sure, I can connect parts together with sprues, no problem. What is the maximum size of the agglomerated part? What is the minimum size of the sprues?

    I guess don't really understand the minimum size restriction. I was thinking it has something to do with feature size but if you're suggesting that I connect my little bitty parts together with sprues to "fool" the design rules into thinking my part is large then I guess that's not the case. Thanks!
     
  12. 65166_deleted
    65166_deleted Member
    Hey JuliaDee,

    Elasto is not a good material for small, highly detailed parts. Any embossed detail will grow and any engraved detail will shrink. Anything that is 8x8x8mm will print out with little details and probably a huge size difference than what is intended. It might grow to be about 1.5x1.5x1.5mm once printed.

    Second, having a lot of loose parts in the build makes the entire tray harder to depowder. Right now, our production facility has asked for a bigger minimum box size.

    You can sprue them together, but make sure the sprues you use is 1.5mm in diameter, otherwise it would likely break in production.

    Last, please remember that this material does indeed grow. Any items that needs to be tight fighting or accurate down to the millimeter, I would try in another material. Embossed parts tends to "grow" up to 0.8mm and engraved details can shrink up to 1.0mm. For something that's super small, 0.8mm is basically doubling your size! The minimum bounding box are there for a reason (to prevent designs that lose all detail in printing, to print designs that "grow" to where the size doubles).. so even if you "fool" the rejection, this is still very much a reality.

    I hope that helps, let me know if you have any more questions.

    Thanks
     
  13. max. bounding box volume:
    27 x 22 x 17 centimetres

    sprues:
    same as min. wall thickness (1,5 mm)
    For BE, I suggest to use round sprues with a diameter of 1,6 mm.


    It's not just "fooling the rules", it's also a legitimately way to safe money. ;)
    Shapeways' production staff can handle it as single item - no searching for tiny models below all that support material, less "is everyting there?" counting...
     
  14. OK, that is definitely not going to work for me (assuming you meant that it will grow to 1.5cm, not 1.5mm); I need dimensional accuracy. I guess I'll have to design a mold and cast the parts in silicone.

    Thanks,
    Julia
     
  15. Thanks for the explanations, pfieffer, makes sense.

    Julia