Author Topic: Permanently marking PCBs  (Read 1522 times)

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Offline artagTopic starter

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Permanently marking PCBs
« on: June 06, 2023, 02:46:19 pm »
I often have a need to write on PCBs, typically to record a serial number or mod level. But all the markers I've tried (includes Sharpie, Lumocolor, and pens rated for glass) seem to convert into dry-wipe when they encounter solder resist.

Has anyone found a reliable marker that will resist fingers, alcohol etc.  ?
Is there a surface treatment (such as silkscreen ink) that will make an area more resistant to cleaning than solder resist ?
 

Offline PlainName

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Re: Permanently marking PCBs
« Reply #1 on: June 06, 2023, 03:15:21 pm »
Tungsten scribe
 

Offline artagTopic starter

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Re: Permanently marking PCBs
« Reply #2 on: June 06, 2023, 03:27:52 pm »
lol. Good permanence but low contrast.

Also - I didn't put this in the original requirements but polythene is another material that I have difficulty marking permanently, and although tungsten will indeed work it degrades the material badly.
« Last Edit: June 06, 2023, 03:33:53 pm by artag »
 

Online mikeselectricstuff

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Re: Permanently marking PCBs
« Reply #3 on: June 06, 2023, 03:28:22 pm »
I find permanent markers fine on resist - I use Staedler Lumocolor fine markers, but pretty much any permanent marker I've used is fine.

The only issue I see is finding a marker that's impervious to solvents when cleaning/reworking.

Also I always put a white silkscreen block for marking
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Offline artagTopic starter

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Re: Permanently marking PCBs
« Reply #4 on: June 06, 2023, 03:39:17 pm »
It may be that colour is also an issue. I've tried various black ones for marking channel number on some radio transmitters. They get a lot of handling and it eventually (ie too quickly) rubs off.

I remember that when we used to make PCBs with hand-applied etch resist many years ago, lumocolor red was recommended and, further, was not useful in the USA because they used a different ink formulation there. So it could be that some pigments are tougher.
 
 

Offline asmi

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Re: Permanently marking PCBs
« Reply #5 on: June 06, 2023, 07:01:42 pm »
Some label thermal printers can "print on" (more like burn into) a plastic tape which should be resistant to chemicals. Have you tried something like that?

Offline voltsandjolts

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Re: Permanently marking PCBs
« Reply #6 on: June 06, 2023, 07:59:19 pm »
Permanent marker then paint some clear electronics lacquer / conformal coating over the top of it.
 
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