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Visual Inspection of PCBA

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#83543

Visual Inspection of PCBA | 9 October, 2019

Hi, I am new to PCBA manufacture and would like to ask the experienced users whether it is normal to have 100% visual inspection in the industry? Or is AOI and ICT testers if programmed correctly enough?

Thanks in advance

David

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DWL

#83546

Visual Inspection of PCBA | 9 October, 2019

In my experience 100% visual inspection of a first article is good but visual inspection of production boards is not really useful, if you have AOI and ICT. If your process is good and defects are uncommon, human inspectors go on autopilot and miss most of the defects that cross their path.

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#83548

Visual Inspection of PCBA | 9 October, 2019

Hi Aurther, Thanks for a prompt reply. I agree but unfortunately our AOI is 2D and misses a lot of solder defects especially on connector terminals which are surface mount. We are also dependent on operator at AOI to mark the defect if caught by AOI. Basically even the AOI is at the mercy of the operator.

Attachments:

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#83551

Visual Inspection of PCBA | 9 October, 2019

I think you answered your own question by providing new information.

If your AOI isn't capable of catching the vast majority of SMT soldering issues and you're SMT process isn't functioning at a very high level, you probably should count on inspectors with some good microscopes. We have to do it too, unfortunately.

In some cases our work instructions specify which parts we need QC to look at visually and in other cases it's across the board.

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#83552

Visual Inspection of PCBA | 9 October, 2019

I'm curious why would you have a solder defect on a connector like the one you show, even if you were putting it down with tweezers. If you are getting lots of such defects, its really not inspection you should be looking at, its the cause.

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#83557

Visual Inspection of PCBA | 10 October, 2019

Dek without SPI and P&P very old.

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#83558

Visual Inspection of PCBA | 10 October, 2019

well if the issues are consistently in the same kinds of places, that at least makes it more likely a human wil spot them reasonably consistently. If they are not consistent and easily documented, people will not spot them and the time spent trying to spot the issues is just money you could spend fixing/upgrading you printer or placement, sending faulty stuff out of the door will cost you more in the long term.

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#83568

Visual Inspection of PCBA | 14 October, 2019

Any major & stable new advances in the PCBA inspection arena anyone has seen recently?

Marantz were looking into AI for simpler programming & defect analysis, and I saw some papers last year on neural networks & deep learning regarding inspection in the steel industry, and on wafers - but nothing that looks like a tried & tested step change.

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#83570

Visual Inspection of PCBA | 14 October, 2019

It does seem to be very much hardcoded proprietary algorithms with all the parameters and maths done on the local machine. No knowledge sharing between machines or back to the vendor ("crowd sourcing" as it were) no cloud magic etc. VI appears to be unveiling a machine that has "machine learning" right now which might possibly be some sort of advance, or flagrant misuse of a buzzword, who knows. I don't know if these machines ven make use of the power of modern GPGPUs?

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#83573

Visual Inspection of PCBA | 14 October, 2019

Thanks.

The key things for me are decent text recognition (not just checking pixel patterns), and very good component models to speed up programming and debug. We can run multiple board types per hour through ours. Also be nice if there was a decent through hole model; most demo's i've seen have all the parts leaning exactly the same way, so not representative of real boards.

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#83574

Visual Inspection of PCBA | 14 October, 2019

Interesting, the scanner based FAI systems seen more than capable of reading text from what I've seen. I saw a demo of an ALeader AOI the other day @ WNIE and that certainly identifed test on resistors, but thinking back I don't know if it was reading it or just matching outlines.

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#83620

Visual Inspection of PCBA | 21 October, 2019

If it actually reads them, then it's a big departure as our Aleader only looks at pixels.

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#83644

Visual Inspection of PCBA | 23 October, 2019

100% appearance does not mean that programming is correct, can only say that the general direction is correct, the specific small details should be improved during the operation.

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Flexible high speed pick & Place

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