PCB Encapsulants to Annoy Copy Pirates

This is why cars made today don't look like the Pinto.

A company in Redmond Washington was trying the idea on software. I wonder what ever happened to them.

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You also have to match the thermal expansion. This makes it extra hard because you need to balance two things.

I went down the potting road in the past and discovered that an aluminum housing was cheaper to do in production.

You don't even rate the peanut gallery.

That was Retard Gallery Comment.

Right where you belong too.

Quality control is like crowd control. You have riot control to make sure crowds don't get out of hand and you have quality control to make sure quality doesn't get out of hand. This way, people won't want to copy your products.

Read the subject title, Archy!

SUBJECT: "PCB Encapsulants to Annoy Copy Pirates" G > How do you like getting products made that way?

You should get a good, thermally conductive epoxy paint to seal it up in, and *then* coat it with real black body paint, which contains enough Carbon to worry me as a direct spray on, but would be fine as an overcoat on the thermal epoxy. Then, you have a conductively cooled device from the source through the epoxy, and a radiant cooled device from the "heat sink" POV. That paint is pretty good at "emitting" the energy 'behind it'.

:On Thu, 05 Nov 2009 22:37:53 -0600, Vladimir Vassilevsky : wrote: : :>

:>

:>Ross Herbert wrote: :>

:>

:>> One thing you need to remember.. if there are any heat generating components on :>> the board, encapsulation in a hard compound may cause subsequent fracturing of :>> components or solder joints because they can't expand and contract. :>

:>I know an engineer who spent many years mixing different compounds and :>fillers trying to create solid substance with minimal expansion or :>contraction while it is cured, and which will not rip the components off :>the PCB because of thermal effects. This is no simple problem. :>

:>

:>Vladimir Vassilevsky :>DSP and Mixed Signal Design Consultant :>

It is far simpler and more effective to simply dip the whole board in pourable silicone rubber prior to encapsulation with the hard epoxy. That will leave plenty of room for expansion.

Conformal coating can be spray applied or used as a dip, and the coating thickness can be altered by simply buying the right coating to achieve the right thickness desired in a single dip.

Make it too thick, and the security features go away.

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fracturing

You find that out when you beat up ten finished assembly candidates till they fail. Then find out where they failed and why.

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fracturing

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One rude surprise of some conformal coatings: Ferrite beads may no longer work!

Hoo boy was a major Aerospace company surprised when they found this out the hard way.

Apparently a ferrite bead has to magnetostrict to operate per spec. Keep it from doing so and the rules change wildly.

Neato.... The material has to move to act like the specs.

You're an A-GREEG-ious IDIOT.

Silicone dry lube spray, wiped clean. Similar to mold release.

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Beads also make heat when they do it. They are often the most "point source" like heaters in the who design.

Regular opaque hobby casting resins?

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Scotsman's thermal shock.

Maybe... The potting should be resistant to a hot tipped vacuum system. The potting potting compound is removed by melting and burning in an archaeological fashion with a hot vacuum nozzle. afaik...the above is doable. If I can make a potting removal tool, the techno duplicators at 'The Happy Circuit Company' can make a potting removal tool.

Last i saw they were catalytic thermosetting plastics. Not quite to the diallyphthalate class, but pretty good.