hiding IC part numbers

We have gadget we're selling, and we'd like to obscure the part numbers of three small, thin ICs. Currently we're globing the tops with Thermalloy green thermally-conductive epoxy, mainly because we have it and it looks cool, shiny green, when it's cured. But it's messy to mix and takes a day to cure, or an hour or so in an oven.

Any better ideas? Something fast and that looks good. Maybe even different colors for different chips. Needs to be permanent.

Grinding the markings off is messy and ugly.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   
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John Larkin
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Buy and utilize a laser printing device. You can also use it to make UID labels, which you will likely have an obligation to create if you have a cage number.

That way, you would ablate only that surface area which you would need to, and then you can still overlay it with an epoxy mask for further assurance.

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Otherwise, the "concrete cutter" "abrasive wheel" type "blade" on the dremel tool and a VERY steady hand.

Reply to
Chieftain of the Carpet Crawlers

Back in the day we used to "blacktop and remark" epoxy encapsulated ics. But when I try to look it up now I get only hits on counterfeit parts, or parts pulled out of scrapped equipment and prettied up for sale.

You may want to talk to the Markem ink company about a cost effective coverup.

But using ink may be more expensive than what you're doing now.

The counterfeits have the markngs sanded off before the blacktop is applied.

Anyone who really wants to know what you use can decapsulate the ICs

-- we did that all the time for failure analysis and competitive evaluation.

Reply to
spamtrap1888

I've done that on some Skinny-DIP-24 parts using a file or sandpaper, = and if=20 the scratch gray finish is ugly, a quick squirt of spray paint makes it = look=20 OK. Or a label with a proprietary part number. Tiny SMT parts might be=20 trickier. Maybe a CNC engraver or laser etching?

Paul=20

Reply to
P E Schoen

Sandpaper applied uniformly looks ok. Average users will never see it. Do you really care what potential competitors think when they crack it open?

I get pissed off when I can't fix something that's broke. The quality of your obscuring technique is a small increment in annoyment. ;-)

Reply to
mike

Have you considered just removing the original markings, leaving shiny naked chips?

What are the markings made of; what do they dissolve in? Have you tried everything from gasoline to nail polish remover?

Worst case, paint them with acid(/base) and follow with something to neutralize it, rinse with deionized water.

Mark L. Fergerson

Reply to
alien8752

How do you identify a chip by looking at the die?

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Frank Buss, http://www.frank-buss.de
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Frank Buss

John Larkin schrieb:

Hello,

are you looking for a very special inkjet printer? If you want to apply different colors on different chips in a short time, you need a printing mechanism and a special ink cured with UV light.

Bye

Reply to
Uwe Hercksen

Put a CPLD or a uC in it with firmware. Scraping of the markings isn't very effective.

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Failure does not prove something is impossible, failure simply
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Reply to
Nico Coesel

It they are printed, acetone will remove it with one swipe from a cotton swab..

If etched? You need to use a rotary tool which does a nice job and then you spray it with some kind of clear coat that glosses.

why not just pot that area of the board with hard to remove compound? or a UV cure non transparent coating over that area which is very hard to remove.

Jamie

Reply to
Jamie

Hire JT ?

Jamie

Reply to
Jamie

You need one of those rustlers' branding irons that turns your neighbour's brand into yours. How about a rubber stamp that says "LM324"? ;)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
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Phil Hobbs

Give it to a company that specializes in that. Google for 'Iphone teardown' and you'll find several companies that specialize in taking electronic gadgets apart and identify the components.

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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
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Reply to
Nico Coesel

An "air eraser." Paasche is the name-brand model but you'll find knock-offs at Harbor Freight, etc.

It's a mini-sandblaster in an airbrush form-factor. Abrades the chip surface, effectively removing the laser-etched numbering. Should be no more than a few seconds per chip but you would need to make sensible safety arrangements for the airborne grit.

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Rich Webb     Norfolk, VA
Reply to
Rich Webb

They're often (usually?) laser etched, these days. Solvents won't work.

Not a good idea for reliability. Any voids in the package will become toxic, not to mention damage to the leg frame. ;-)

Reply to
krw

Actually, I'm more concerned about customers than competitors.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   
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Reply to
John Larkin

They seem to be laser etched into the surface. Nothing will dissolve them, and it takes a lot of serious grinding to make them unreadable.

Maybe I'll email Master Bond. They seem to like exotic problems.

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John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   
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Reply to
John Larkin

Seriously, how about a branding iron? You can etch nickel with PCB chemicals easily, and if you get the estimable Pablo to braze a chunk of it to a nice hot soldering iron tip, you can put your own markings on the chips and obliterate the old ones in seconds.

Since it's customers you're worried about, I gather you're wringing some high-priced function out of low-priced chips, and want to keep the sauce secret. (Maybe using those step-recovery SMPS chips you discovered?)

Branding them "Highland SuperExperimental Chip #1" would probably do. ;)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal Consultant
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Reply to
Phil Hobbs

Suggest you sit down when you get the quote. They quoted me something like $600 for the minimum size sample of something they've been advertising for months. A bit much considering they had no idea whether it would do our job so we have to buy it on spec and do expensive and time consuming tests?

Reply to
Spehro Pefhany

Way back when, I remarked some chips using screen printing. A bit messy, but looks much nicer than today's legit laser markings. I guess I could dilute the nice white ink down and mix it with black so you could barely read it.

You can buy purpose built part grinders for DIPs, not sure about other packages. The occasional stuff I see with part numbers removed (including some really low end stuff) looks like they did it by hand with a die grinder or some such thing.

Reply to
Spehro Pefhany

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