IDEAS Bigbox Heated Build Chamber

Discussion in 'Guides, Mods, and Upgrades' started by Rajasundar, May 23, 2016.

  1. Rajasundar

    Rajasundar Member

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    I would like to heat my build chamber upto 70°C. I am bit concerned about warping of the printed parts like the carriage holders, extruder mounts of the Bigbox. It seems like they are printed from edge material (PET G) ? The Tg of PET G is around 80°C. Any advice please ?

    My Bigbox is a plywood frame and I have enclosed my Bigbox with plexiglass and insulation foam. I plan to water cool the steppers and hot end.
     
  2. R Design

    R Design Well-Known Member

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    It sounds like you're serious!

    So,

    a) the only way to know is to do a test: take something in edge (a clip from the electronics cover?) load it with an appropriate amount of stress and leave it in the oven overnight...

    b) Tg is not a black and white indication of when polymers start to creep, especially under load. Even without testing there's a strong case for reprinting all the critical parts in something more high temperature.
     
  3. Chase.Wichert

    Chase.Wichert Well-Known Member

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    ABS Tg starts at 100C but has a wide range.
     
  4. Rajasundar

    Rajasundar Member

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    OK thank you. I have put a sample of edge print for testing and lets see how it fairs tomorrow.
     
  5. orcinus

    orcinus Well-Known Member

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    ABS in general is a different story to most polymers we use for FDM, because it's amorphous.

    @OP - i've used PET (T-Glase mostly) parts in places near the hotends to no ill effects (no noticeable creep). Until you exceed the Tg you won't see any softening. Once it exceeds it, it starts going soft fairly slowly. I'd say you're pretty safe until about 90, but YMMV, depending on the particular mix Edge is. R-design is right, testing is the only way to be 100% sure.
     
  6. Rajasundar

    Rajasundar Member

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    Seems to creep quite a bit at 70°C under a load of 2.5 kg... I think it wouldn't be this bad for an actual loading case considering weight of a hybrid titan dual...i hope


    upload_2016-5-25_17-45-8.png
     

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  7. Chase.Wichert

    Chase.Wichert Well-Known Member

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    It will also help when you have the bearings in and clamped together.
     
  8. R Design

    R Design Well-Known Member

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    Good work.

    The next question is, how much "creep" can your application tolerate?

    1mm?
    0.1mm?
    0.01mm?

    And then,how long will it take to achieve that limit with your intended loading?

    EDIT: Actually, as usual, it's perhaps more complicated than that.

    For example, suppose it mustn't sag more than Y mm during a print.

    But then at the start of the next print, it doesn't matter that it sagged in the previous print (since one can re-calibrate Z-offset).

    Until the sum of all the sagging starts to cause a different kind of problem!
     
    #8 R Design, May 26, 2016
    Last edited: May 26, 2016

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