Overmolding Electronics

[GRF]

I am looking to over mold some electronics for outdoor usage. I am looking for a material where I can put a PCB and wires into a mold. The inject material to complete encapsulate the PCB, providing protection against moister. There will be a couple exposed LED's on the board and the device needs to be with stand exposure to -40C to 50C ambient temperatures. The internal temp could reach as high as 85C when the device is on.

If anyone has a suggestion on material, molding process or suppliers it would be greatly appreciated.

Thank you for your time and help.

 

[ScottyUK]

Over here in the UK we typically use 'potting compound' for encapsulating electronics. Potting compound is usually a urethane or epoxy resin. Maybe worth a Google?


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If we learn from our mistakes I'm getting a great education!

 

[DRWeig]

Over here in the US, we do the same. Generally epoxies is what one finds, but some silicones too -- urethane can also be had, but it's typically used for encapsulant (conformal coating) rather than bulk potting.

Good on ya,

Goober Dave

 

[GRF]

ScottyUK,

I have concerns with potting as I want the top of the LED's exposed and fast cycle time. We are going to make 1.1million of these annually. Potting is too labor intensive and possibility of errors.

I have one supplier here in US that wants to use urethane but the guy in China wants to use ABS. I have concerns with ABS ripping components off the board during molding and with temp cycling.

Ideally both suppliers would use the same material but I do not have direct contact with suppliers in China and there is always a language concern.

 

[GRF]

I should add that the geometry is fairly complex for potting there definitely need to be a mold to form the shape and I need the potting to come up the edge of the leds but not cover them while in other areas the potting needs to be taller than the LED's to cover other electronic devices and the wires and connection points for supplying power.

 

[asimpson]

An experienced overmoulding company should know how to protect components in manufacturing and in the field. There are various tricks like sheet metal shielding for sensitive areas. Light guides for LEDs.

 

[IRstuff]

Whatever epoxy they use for plastic packaged ICs works pretty well. And they're cranking millions of parts per month.

TTFN

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