Electronics Potting

Discussion in 'General Electronics Chat' started by cl10Greg, Mar 4, 2015.

  1. cl10Greg

    Thread Starter Active Member

    Jan 28, 2010
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    0
    Hello,
    I was curious if anyone knew how some of these potting machines work for electronics? The question I really have is how they mix and dispense the two part epoxies? I can see the following scenarios:
    • Have the machine have a single hopper that has the combined parts already and it dispenses the mix. Seems logical but also have to consider usage time before it dries.
    • Have the machine have two hoppers that pour into a mixing chamber that does the mixing and then dispenses. Could have issues with the mixing chamber and cleaning.
    • Have the machine have two separate dispensers and have the epoxy added one at a time into the case. Since the two parts really aren't mixed together, this could not work at all or work very inconsistently.
    What are your thoughts?
     
  2. #12

    Expert

    Nov 30, 2010
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    6,813
    I have seen nozzles that did a swirl effect to mix the ingredients, but I am no expert. However, I would say that any cleaning problems are much easier in a replaceable plastic nozzle than they are in a holding tank.

    We had a thread here about removing potting compounds and it turns out to be a gigantic struggle, even if you know the chemistry involved. The only reasonable answer seems (to me) to be disposable parts.
     
  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
    2,795
    1,236
    Assuming I correctly understand your question, you may find [some of] the following points useful...

    -With reference to the (admittedly few) operations with which I am familiar, mixing is accomplished 'on the fly' via pneumatics in the injector ‘heads’.

    -Potting of electronic/electrical assemblies in resin is performed under hypobaric conditions.

    -As regards cleaning, epoxies (even once fully polymerized), are rapidly degraded by most ketones (i.e. dissolution of the 'binder' with consequent 'precipitation' of the filler).

    Best regards
    HP
     
    Last edited: Mar 4, 2015
  4. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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  5. wayneh

    Expert

    Sep 9, 2010
    12,128
    3,049
    Known as "static mixers". The energy for mixing comes from the supply pumps instead of an agitator.
     
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