Electrical Engineering & Electronics Design

Depends on the level of sealing you need and the pcb topography. I've used acid free silicone in a molding box with great success in the past.

The most common way to seal components is with 'conformal coatings' which can be clear or opaque (black). They are widely used in many applications and industries, very cost effective, reworkable, and provide a high level of environmental protection.

Beyond that there is encapsulation which involves a potting cavity and a potting material. If there is a custom cavity, this is a moderate expense.

Beyond that there is injection plastic over-molding that can be expensive for tooling costs.

If there needs to be security protections, then full custom die shielding from the semiconductor manufacturers is the most expensive.

thank you for your responses.

these are the basic requirements

1) security reasons : hide the PCB (with opaque non removable resins)

2) Protect the PCB from thermal(till 70 degree Celsius), physical shocks, moisture/ water vapour.

3) less cost.

4) non expansion resin

Are silicone coatings removable?

Can conforming provide me the required results or encapsulation is better? Security of the PCB is the main Requirement, followed by thermal protection .

Many thanks

By Security of PCB, I mean hiding the components so that it can't be reverse engineered.

Anything can be reverse engineered with the right technologies and amount of money, but in general for a low cost solution potting is the method most designs are shrouded from peering eyes. But if someone wants to reverse engineer your design - it will happen !

Absolutely true! A current project I am working has to go through PCI compliance testing for the hardware - the way the lab explained it is this: certification depends on how much time and how much equipment they need to hack the device, not whether or not it can be done... How does that make everybody feel about their financial information?

Regards,

Steve

Thanks Steven

Honestly I worked for Hypercomm (Scottsdale) before they were acquired by VeriFone (Sacamento) and the time and money invested in 'secure' payment card readers wasn't worth the time. It became #1 over the previous lead by Ingenico (French).

The most common way of getting data today is thru RFID / NFC readers or thru WiFi / Bluetooth eavesdropping as the transaction is occurring. The PCI industry doesn't seem to care as they haven't changed their ways.

I have presented alternate low cost solutions that are 99.999% secure relying on very little and low cost hardware, but I came to the conclusion that the PCI industry doesn't care since false and fraudulent transactions mostly hurt the consumers and the retailers. They only pay lip service to the issues and consider it a cost of doing business.

FYI - the PCI industry is controlled by the French and they make it virtually impossible to pass their tests as they tell you very little of the requirements and the testing methodologies. Also there are many PCI cards types that are widely ranging.

My experience.

While I have never gone to this length, A colleague placed lead sheets around the board before potting, and also left a few low current lines off the board and used relatively light wires to make the proper connections supported by the potting compound. Any attempt at X-ray examination or actually mechanically removing the potting would either produce no results or destroy the connections. He also sanded the component labels / color codes off most of the components.

Yeah, he was paranoid, but having had one of his designs reverse engineered he felt justified in this.