How to Differentiate Class 3 and Class 2 products in terms of process

I've always approached it like this: Design your processes and perform your work to class three standards, and inspect to the standard that is acceptable.

That is, all work should be performed to the highest degree of quality. When the work is inspected, though, inspect to the level that is acceptable. There's no sense in spending time and money reworking items that are acceptable to class 2 standards when delivering class 2 work. As an example, take barrel fill on through hole devices. Class 2 allows 75% barrel fill with solder wetted to the lead of the device; class 3 requires 100% barrel fill, with solder wetted to the lead. When delivering class 2, do not spend the time to rework a joint that is acceptable (do spend the time to improve your process, however).

Is microscopic inspection necessary? That depends on your eyesight :) I inspect everything under a scope, because I don't feel that I can adequately examine some solder joints without the magnification.

Cheers, ..rob

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The closer your inspection the more defects you will find, the more rework you do the possible cost you will add and the potential increase of damage you could do to your products if rework is not up to a machine copyable standard.

"Is there any inspection process which differentiate class 3 with other classes. such as 100% microscopic inspection, 100% dage" This (and someone quote me if I'm wrong) kind of inspection is not governed by class in IPC-610 but by land width and land diameter groups.

X-ray is more associated to void inspection.(which is governed by class(and different component types))

you cannot really easily outline what differences you need between class 2 and class 3 and there could be many or only a few. It depends on the product you make.

Class is outlined by the customer or your R&D team.

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