4 ms·

Thank you for the insight. I was rather naively imagining that every board is subject to some kind of x-ray image matching with the original PCB design to find

Thank you for the insight. I was rather naively imagining that every board is subject to some kind of x-ray image matching with the original PCB design to find differences. Not that simple, I see.

crispyambulance 8y ago
Some manufacturers do X-ray boards. Typically this is done to check that BGA devices (https://en.wikipedia.org/wiki/Ball_grid_array https://en.wikipedia.org/wiki/Ball_grid_array) are soldered properly. Usually not done on every board, but only if there's a problem suspected. When it happens they tend to focus only on particular BGA components or suspect copper traces rather than the whole PCB.
- extrapickles 8y ago
  Usually you scan boards at a percentage determined by statistics (SPC can get complex). However the checks are automated, so you would have to perform the checks in a different trust zone (eg: different country).
- scoggs 8y ago
  I'm guessing the answer is obviously yes that this type of x-ray would easily be able to discover / distinguish something the size of what's been described? (1mm x 2mm from what I've seen thus far?)
  - PeterisP 8y ago
    The x-ray picture would contain information sufficient to detect that thing, but it's quite plausible that the process/procedure of analyzing that x-ray would not find it. If they're looking for extra hardware, they're going to detect it, but if they're looking for bad solder joints, they're going to detect bad solder joints but not extra harware.
    - scoggs 8y ago
      Right. It doesn't exactly align with what a normal auditor would be looking out for, I suppose. Thanks, I appreciate it.
- avip 8y ago
  I've only seen X-ray as a destructive test. AOI is pretty commonplace on a per-unit base, but whether it could or could not detect some modification depends on lots of details we don't have.
btashton 8y ago
It's not uncommon at all to do AOI on all or a percentage of the PCBs. X-ray is more useful to identify solder issues or defects in the raw PCB itself.
- avip 8y ago
  Exactly. I've never seen x-ray used post SMT. We've used it to post-mortemly debug BGA issues.

Thank you for the insight. I was rather naively imagining that every board is subject to some kind of x-ray image matching with the original PCB design to find differences. Not that simple, I see.

crispyambulance 8y ago

Some manufacturers do X-ray boards. Typically this is done to check that BGA devices (https://en.wikipedia.org/wiki/Ball_grid_array https://en.wikipedia.org/wiki/Ball_grid_array) are soldered properly. Usually not done on every board, but only if there's a problem suspected. When it happens they tend to focus only on particular BGA components or suspect copper traces rather than the whole PCB.

extrapickles 8y ago
Usually you scan boards at a percentage determined by statistics (SPC can get complex). However the checks are automated, so you would have to perform the checks in a different trust zone (eg: different country).
scoggs 8y ago
I'm guessing the answer is obviously yes that this type of x-ray would easily be able to discover / distinguish something the size of what's been described? (1mm x 2mm from what I've seen thus far?)
- PeterisP 8y ago
  The x-ray picture would contain information sufficient to detect that thing, but it's quite plausible that the process/procedure of analyzing that x-ray would not find it. If they're looking for extra hardware, they're going to detect it, but if they're looking for bad solder joints, they're going to detect bad solder joints but not extra harware.
  - scoggs 8y ago
    Right. It doesn't exactly align with what a normal auditor would be looking out for, I suppose. Thanks, I appreciate it.
avip 8y ago
I've only seen X-ray as a destructive test. AOI is pretty commonplace on a per-unit base, but whether it could or could not detect some modification depends on lots of details we don't have.

btashton 8y ago

It's not uncommon at all to do AOI on all or a percentage of the PCBs. X-ray is more useful to identify solder issues or defects in the raw PCB itself.

avip 8y ago
Exactly. I've never seen x-ray used post SMT. We've used it to post-mortemly debug BGA issues.