Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Manual Visual Inspection Benchmarks


Manual Visual Inspection Benchmarks | 13 June, 2001

Is anyone aware of benchmarking data to suggest what is best-in-class (and average) performance for manual visual inspection?

We would like to better understand what percentage of defects going into the process will be screened out. This provides us something to use in comparison and justification of alternate methods (i.e. AOI, AXI, test).

Great if we could also understand "best practices" for this process as well. Has anyone put effort towards the study and improvement of this process? Is inspection only used to provide insight into the performance of other processes and never formally optimized?

reply »


Manual Visual Inspection Benchmarks | 13 June, 2001

We use a great concensus document for inspection. It is: IPC-A-610C, Acceptability Of Electronic Assemblies as the basis for accepting assemblies. You can find it at IPC []. [Help!!!! I�m turning into an IPC Cal.]

We find that many different things cause inspection rejections vary. AOI seems to be a great leveler. The question becomes: How many of these machines can you justify?

reply »



Manual Visual Inspection Benchmarks | 14 June, 2001

Hi mate,

AOI seems great for : 1) missing 2) wrong parts 3) wrong orientation 4) x-y axis misalignment 5) upside down placement 6) etc.....?

AOI shucks for : 7) unsolder (joint) defect 8) tombstone / tilt

My guys are evaluating AOI m/c, for substitue for our manual visual inspection techniques, appreciate if you would share any further AOI eval findings, here with us.

Thanks :)

Agree with Dave.F, IPC-A-610 standards covers, the industrial stand point, on visual inspection criteria,

IPC can be ambiguous at times, filled with grey areas, depending how you interpret it, so fall back on your customer defined specs. and good'O common sense, as they say :

"give strength to your arguements, and true enuff, they manifest...."

Regards, ianchan / QA 14 june 2001

reply »


Manual Visual Inspection Benchmarks | 14 June, 2001

No problem with the workmanship standard. Our staff are all trained in the C rev and we use it as our standard. Most of our clients are referring to it as well.

The main problem is with untested product. We currently rely on manual visual inspection as the only means to verify compliance with the relevant workmanship spec for these products.

How can I predict what the DPMO will be coming out of inspection? I'm sure I could plan some data gathering to determine this but this doesn't tell me where I should be (average) or could be (best-in-class). I need this info to help in justifying test (or other solutions) to our clients and ourselves. Want to put an end to the "shouldn't have inspection caught that" syndrome.

reply »


Manual Visual Inspection Benchmarks | 14 June, 2001

We rate each board for producibility. [Our rating chart may be based on some things that Bob Willis did. Check his site [ ] for all kinds of neat stuff. Maybe even bring him in to help you sort through things.]

There is a fair amount of correlation between our rating and build-to-cost. We have never drilled into the type detail you seek. But then again if your building to cost, who cares about the rest of the stuff, eh?

reply »


Manual Visual Inspection Benchmarks | 27 May, 2003

Can anyone add any new info to this old thread? We be great if a study was available detailing expected performance and factors that can have an impact like complexity, fatigue, etc. Lots of AOI mfrs claiming that there are studies on this but noone identifies them.

Thanks in advance...

reply »

vacuum tweezers - manual pcb assembly

PCB X-Ray Inspection System