250 mm wall in Strong & Flexible: How to prevent warping?

Discussion in 'Technologies and Hardware' started by feklee, Feb 20, 2014.

  1. feklee
    feklee Well-Known Member
    The length of the below profile is 250 mm. What should be the minimum wall thickness for printing in Strong & Flexible without warping?

    Notes:
    [list type=square]
    [*]While the side walls should be thin, I have the liberty to make the bottom quite thick.
    [*]I prefer to print in black, and I assume white and black have the same material properties.
    [/list]
    profile.png
     
  2. stannum
    stannum Well-Known Member
    Everything is printed white SF. Then polished & dyed as needed.
     
  3. feklee
    feklee Well-Known Member
    Then why is the minimum bounding box (230 × 180 × 320 mm) for black larger than for white polished (150 × 150 × 150 mm). Is black Strong & Flexible not polished before dying?

    Anyhow, suppose I use white polished, what wall thickness should I choose to prevent warping?
     
    Last edited: Feb 21, 2014
  4. AmLachDesigns
    AmLachDesigns Well-Known Member
    Polished bounding boxes are smaller than non-polished - a constraint of the polishing machines, I believe.

    There is no polished BS&F - I think the colour results were not satisfactory.
     
  5. feklee
    feklee Well-Known Member
    Indeed. I contacted Shapeways support and learned:
    [list type=square]
    [*] Black models are not polished, because: "[...] when we polish the models and dye them in black it will leave some white spots on the model."
    [*] The boiler where the models are dyed allows for a maximum model size of 230 × 180 × 320 mm.
    [/list]
    What remains is my question about dimensioning wall thickness.
     
    Last edited: Feb 22, 2014
  6. AmLachDesigns
    AmLachDesigns Well-Known Member
    Yes. Why do you think it will warp? On the materials page it does mention this but, it seems to me, only from the point of view of stiffness/gravity concerns.
    The U-channel you have designed would seem to be inherently stiff, but the application you have in mind is also important.

    I'm guessing the thickness you are envisaging is around 2mm which will still flex, but is reasonably stiff.
     
  7. stannum
    stannum Well-Known Member
    250 length would force a wall of 2.14mm. Why? Forgot. There was a calculator (1:117 ratio, minimum thickness 0.7mm) and an explanation, not anymore after one of the multiple website redesigns. Maybe you can try smaller and get a reject, maybe it will pass with less.
     
  8. feklee
    feklee Well-Known Member
    That's what I expect. Thanks for your opinion!

    Anyhow, I am just thinking about a redesign which would not require such a long profile at all. It feels really hard to design without knowing the material well and the printer being far away. I guess it's best if I let print several variations of the same design, then iterate from the one which works best.
     
  9. feklee
    feklee Well-Known Member
    Thanks!

    As I just wrote, it's probably best to submit the same design in several variations, because without a printer at home, it's hard to just experiment.
     
  10. stannum
    stannum Well-Known Member
  11. feklee
    feklee Well-Known Member