Board buying
Don’t Let Perfection Be the Enemy of a Perfectly Good PCB
How well does your incoming inspection team know the acceptability standards?
Does your PCB quality team inspect to pass or inspect to fail? Knowing the difference between what is rejectable in a printed circuit board and what is a nonissue is more important than ever.

Skyrocketing costs, shortages of copper and fiberglass materials, and longer delivery times mean remakes are not available as quickly as before. Rejecting PCBs for things that don’t affect the form, fit or function of the final project is simply bad business.

To be clear, I am not advocating acceptance of substandard product. IPC-A-600 standards are clear as to what is good and what is not. But thanks to lack of training or misinterpretation of industry specs, incoming PCB quality inspectors are turning away perfectly good commercial-grade boards that then must be remade.

The main culprit in this cycle of unnecessary PCB rejection and remake costs is management, which fails to provide adequate training to incoming inspectors and instills in them a fear of releasing bad product to the manufacturing floor.

At one high-mix EMS customer of mine, inspectors are so sensitive to any possible issue, they routinely send rejection notices over even the slightest blemish in the solder mask. This leads to a lot of time spent on calls back and forth, then additional paperwork, and then a hefty freight bill for the remakes. In the end, the very same boards that were rejected are accepted, and a lot of time and money has been wasted.

Another one of my customers recently rejected a large, heavy PCB for a slight corner ding. The photos made the issue look worse than it was, and the impression given was the entire lot was affected. The boards were returned.

Of the 10 boxes returned, all but three had the original factory seal, meaning the product inside was never inspected. And of the three boxes that were inspected, only one package of boards had the issue for which the entire shipment was rejected. The dings were minor and, according to IPC, acceptable “as is.” The PCBs were cleaned up, repackaged, and immediately returned. The request for the supplier corrective action was respectfully declined, citing the IPC specification that the boards were acceptable. The supplier offered to send the relevant specs to the customer, but the customer declined, saying it understood the specs. If the customer did indeed have a strong understanding of the specs, the boards would have never been returned in the first place, and UPS would not have become even richer than it already is.

No PCB fabricator wants to accept the return of boards unnecessarily, as I am sure no PCB assembler wants to delay its customer over a nonissue. The time, money and paperwork required to resolve a nonissue is a burden that can usually be resolved with a couple phone calls.

But that resolution can’t happen without proper training. One owner of a PCB assembler told me he didn’t “want an hourly employee releasing bad product to the floor, causing tens of thousands of dollars in scrap.”

But by not giving that employee enough training to recognize the difference between a perfect PCB and a perfectly good one, the owner is likely costing his company even more in monthly revenue with boards that are needlessly scrapped, which prevents shipment of finished assemblies.

I’ve often seen an OEM overrule its EMS provider over a nonissue on a circuit board. Yes, OEMs want quality product, but they also want that quality product delivered on time. It looks bad for the EMS to cause delays that could have been prevented with additional training for inspectors.

How well does your incoming inspection team know the IPC “acceptability” standards? Those standards define what is an acceptable PCB that does not need to be rejected for minor flaws that do not affect the performance of the board. In other words, they are designed to prevent the perfect from becoming the enemy of the good.

Training sites around the world offer help to PCB inspectors to sharpen their ability to recognize nonconforming conditions. Many are tied to the IPC-A-600, “Acceptability of Printed Boards” certification program, which “describes the preferred, acceptable, and nonconforming conditions that are either externally or internally observable on printed boards.” In addition, organizations such as SMTA and publications such as this one host informative seminars (both online and in-person) about what is acceptable and what is not.

And don’t forget industry trade shows like PCB West (coming in October to the Silicon Valley). Plenty can be learned from industry experts on the acceptability issue.

Investing in additional training for incoming PCB inspectors is worth the time and money. Being able to make the proper call when a board issue presents itself will allow your operation to consistently produce quality product in a timely manner and make your company a trusted partner for its customers.

Greg Papandrew portrait
Greg Papandrew
has more than 25 years’ experience selling PCBs directly for various fabricators and as founder of a leading distributor. He is cofounder of Better Board Buying (boardbuying.com); greg@boardbuying.com.