3D Printer Electronics Enclosure - Please Review

Discussion in 'The Projects Forum' started by danl, Jul 3, 2015.

  1. danl

    Thread Starter Member

    Sep 24, 2013
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    I'm building a large bed (24x24") 3D printer. This forum has already helped greatly by reviewing the circuit. Attached is a design for the enclosure.
    The components will be mounted as shown on an aluminum plate, 18 x 12 x 3/32". The plate will be grounded and serve as a common ground.
    The SSR and heat sink will be mounted on a 90 deg bracket so they are horizontal on the plate vs vertical.
    The cover will be 3D printed from PLA (the plastic used in microwaveable trays, etc). Has ventilation slots.
    The backplate will be directly screwed to the metal framework of the printer, and the cover screwed to the plate. enclosure layout cover w.jpg enclosure layout w.jpg
    Any comments, advice much appreciated.
    Thanks.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    It is funny, the #1 parts made by 3d printers is more parts for personal 3d printers.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Wise to allow for expansion, generally Murphy's law applies to electrical enclosures, the required calculated size always equals less than finally required in practice!:(
    Max.
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Hopefully the maximum temperature reached by any component contacting or very close to the cover will be less than the melting point of the PLA ;).
     
  5. danl

    Thread Starter Member

    Sep 24, 2013
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    Wow, you guys respond really fast! Thank you!
    So, given I'm a total electronics rookie, no one sees any problems with the design?
    It looks safe, functional? Anything that could be made better?
    PLA melts at 150C(300F), and the SSR is rated way above the load (25A vs 11A), and it will be on a heat sink.
    The power supply will be way over-rated too. So I don't expect any T's near even 100C.
    Sound right?
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The custom for electrical/electronic enclosures is to enter power at the top, where fuses/OL's etc, also heat producing items are kept at the top, power TXFR's etc.
    Max.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The power supply probably is 75% to 80% efficient, and the SSR will dissipate around 20 W. Fans?

    ak
     
  8. danl

    Thread Starter Member

    Sep 24, 2013
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    Ah, a fan will be added if things get too steamy. Maybe like a 80mm?
     
  9. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    I recommend 12v heaters. A lot happens to wire, insulation solder joints after hours at high temp, vibration from your stepper motors studdering there way through the part. A broken 120v wire makes a bigger issue than 12v.
     
  10. nerdegutta

    Moderator

    Dec 15, 2009
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    Care to show the posts. I can't find them?
     
  11. danl

    Thread Starter Member

    Sep 24, 2013
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    120V was used because at 12 and even 24V, amperage and wire size were too high.
    Heater is 1300W:
    @12V = 108A
    @24V = 54A
    @ 120V = 11A....manageable wire sizes and standard construction/readily available silicone heaters.
    Heater wires are the only 120V. Steppers, extruder, etc are all 12V.
    Heater wires only exposed to z-axis movement. That's slow and only fractions of a mm at a time.
    The build plate does not move in the xy axes.
     
  12. danl

    Thread Starter Member

    Sep 24, 2013
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  13. nerdegutta

    Moderator

    Dec 15, 2009
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