Encapsulation of PCB with Epoxy 1

[richidinho]

Hello everyone,
I have to fully encapsulate a printed circuit board (PCB). I chose to use epoxy resin. Though, I would need suggestions about the molding: how can I mold a 3D fully covering shell around the PCB in order to achieve hermeticity? I don't know how to place the PCB inside the mold in order to put it in the center of the capsule. Thinking about using a support or something like this. Open to advises!! thank you in advance

 

[IRstuff]

There are specific materials intended to environmentally protect PC boards. Urethane-based and parylene coatings appear to be the most prevalent.

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[dgallup]

Lots of automotive parts like ignition coils (which contain PCB's these days) are epoxy coated. However, the electrical components are placed in a molded polyester housing and the epoxy is poured in then cured.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[IRstuff]

Sure, with potting, you can get away with less forgiving materials, but that would seem to me to be overkill from a weight and volume perspective, and seems to be a very retro approach from a time when acceptable conformal coating materials didn't even exist. Conformal coatings are VERY thin, and allow you to go back in and verify failures or corrosion without spending a truckload of time and money de-potting the boards.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[richidinho]

Thank you for the advises, unfortubately it not an issiue about the materials but about the processing. I will figure out solmething and test it, thank you anyway for the suggestions!

 

[1gibson]

Gotta have wires coming out somewhere, use those as a fixture to center the board in a mold? Does the board float or sink in epoxy? Use gravity to your advantage, with one wire and the right tilt of the mold, you should be able to get it.

 

[IRstuff]

You don't necessarily have to do it all in a single step. While process control might be challenging, you could have it partially processed with some means of holding the board, and once that part is cured, or cooled, or whatever, you could remove the supports, and complete the processing. The seam might be a problem, but it's a process control issue at that point.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[jose0012000]

I do not know if I well understand you:
I built a steel box where I set the PCB with connecting windows. Next, I select my epoxy resin based on requirements to encapsulate the PCB. Previously, PCB circuit is protected with other adhesives to consolidate and seal the PCB.

 

[sreid]

http://www.dolphs.com/

 

[tnatale]

This is fairly straightforward. The are two possibilities, primarily depending on the board quantities. If larger volume, have a tray made that holds the board. Place the board in the tray and then fill the tray with epoxy. Tray, board and epoxy make the final assembly.

For lower volume boards, take a piece of glastic as a base and then use 90° angle glastic to make the frame (screw the angle to the base so make the frame. Caulk all the joints with a 100% silicone. Once everything has cured, apply a silicone grease across the entire inner surface of the mold. Add the board, epoxy and cure. Once cure remove the board from the frame. Wipe the frame to clean and apply a new coat of silicone grease.

In both cases you may need to use greased plugs, etc to temporally cover any areas that are not going to get epoxy.

Finally, I always preferred to use a soft epoxy as the potting compound.

Good Luck