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Fresh PCB Concepts: Can Better Guidelines on Cosmetic Failures ‘Save’ Functioning PCBs?

Sitting in my home office, writing this month’s column due to social distancing caused by the COVID-19 outbreak, I realized it was March 18: Global Recycling Day. April’s topic could not be more suitable. Should we go green, recycle more PCBs, or save working ones from being scrapped?

Green manufacturing has been on everyone’s lips for a long time. However, it feels like one of those buzzwords that just doesn’t get the buzz it deserves. In Norway—particularly in Oslo—over the last years, we have seen “the green wave” hit us. The world experienced the leadership and “young green enthusiasm” of Swedish Greta Thunberg. The green wave is sweeping the world, but are we missing an easy and quick fix in the industry to be even greener?

RoHS and REACH teach us that substances and chemicals used in electronics are not to be thrown away and can be toxic to nature. We create laws and standards that restrict us from using metals from restricted mines and smelters and substances that can infect nature when disposed of. At the end of the life of any electronic product, we have rules on how to separate the most toxic elements. Home appliance electronics are taken back by the shops and manufacturers, and we dismantle and recycle them. The process goes on.

Why Do We Reject Good Products?
Why does the electronics industry reject good products when it’s not always needed? Every year, fully functional PCBs are scrapped due to cosmetic “failures” that are not approved. Is this right, or do we need to make an even more precise set of rules on how to handle this not only to avoid unnecessary claims but also to save the environment? Can a more conscious approach and education on what to be considered as failures help make the industry to be greener?

Form, Fit, and Function: Not Functioning?
The defects I’m addressing in this column can be small scratches, solder mask discolorations, minor copper residues, inclusions, and other defects. All of these are minor and accepted by IPC-A-600 and IPC-610 or not mentioned. Why are such issues not in the standard?

If you look at IPC-A-600, it focuses on issues that affect form, fit and function. A rule that is repeated in almost every chapter is acceptability—unless it reduces the spacing, hole diameter, or line width below the limits specified in the procurement documentation. This means that the designer should give restrictions for minimum insulation distances allowed on the finished PCB.

My experience is that very few designers provide this information, which means we should follow default rules according to IPC standards. But that also brings us to all the open questions IPC calls AABUS, or “as agreed between user and supplier.” IPC requires these questions to be discussed between the user and the supplier, which is worth a separate column itself. In addition to these documented issues, we have a cosmetic “gray zone.”

To read this entire column, which appeared in the April 2020 issue of PCB007 Magazine, click here.