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30 The PCB Magazine • September 2017 Introduction Change is a given. While this adage may be quite true and normally a good thing, it can wreak process engineering havoc in a printed circuit operation. Change is good, but the op- erative word is controlled change relative to the complex processes involved in manufacturing a printed circuit board. The key to successful- ly navigating process change is to develop a ro- bust Temporary Process Change (TPC) program. Process Engineering: 75% Science, 20% Black Magic and 5% Luck My process engineer friends will certainly take exception to this statement, however, no matter how talented our process gurus are, I be- lieve I could make a compelling argument with them over a couple of beers. It is incontrovert- ible that two plus two will always equal four, no matter who is doing the math. If printed circuit process engineering was 100% science, then what works in one shop would work just as well in every other shop, period. We all know that is about as true as the statement that "poli- ticians never lie." That is why it is so important, once the process recipe has been engineered to be highly repeatable, to have a controlled meth- od to continue to tweak and improve it. Even in the most controlled manufacturing environment, internal audits, rework and yield issues can oftentimes be traced back to an un- authorized minor process change. Changing a bath temperature or time, skipping a traveler step, or changing the supplier for a consumable may seem like a good idea at the time—until everyone is scratching their heads over a spike in scrap. Operators, leads and supervisors have their hearts in the right place when they want to try an idea to improve a process. More times than not they simply lack experience with the DoE (design of experiment) or other controlled change methodology. Process Overview When crafting the program, the first thing that needs to be fleshed out is what function will serve as the watchdog of the system, which is the first mission-critical decision of a TPC program. Employee engagement and creativi- ty must certainly be fostered while at the same Navigating Process Change? TPC is the Key FEATURE COLUMN: THE RIGHT APPROACH by Steve Williams THE RIGHT APPROACH CONSULTING