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R-E-S-P-E-C-T the PCB
The Wind Beneath Whose Wings?
When it comes to making printed circuit boards, fabricators often find themselves feeling like Rodney Dangerfield, devoid of all due respect. While Semiconductors and ICs bask in fanfare and glory, the stuff they sit on remains a thankless tangle of copper and laminate. PCBs have been cast in a role as forgettable as Barbara Hershey in the shadow of Bette Midler in Beaches—with no Wind beneath My Wings at the end of the day.
For this reason, I thought I would spend a few blog posts putting a spotlight on the wonder of the PCB and those who make them. We have grown desensitized to the true marvel they are and compare their significance to other commodities and plastic play-things made in Asian countries. Therefore, the value we place on PCBs gets diminished and marginalized, which can get you into some serious trouble if not kept in check. This is particularly true when it comes to RF and Microwave PCBs.
The Myth of the Budgetary Quote
It is not unusual to get an email requesting a quote for a PCB that goes something like this:
“Can you please give me budgetary quote for 50 pcs. of a 4 layer board on Rogers 3003, which is approximately 2 X 3 inches?”
C’mon, really? I think this happens because many have perpetuated the myth that a board can easily be quoted according to a price per square inch. This is only true if you have very plain vanilla boards with standard features. Otherwise, the factors to be considered are too complex to break down into a simplistic equation. In the above budgetary RFQ, for example (that has an RF/MW or high performance application), there is a high probability that the lines are very fine, that there are buried or blind vias, that there is a cavity that opens to an internal ground plane, that the hole density is very high, that one or more layers may be FR-4, that it has a nickel-gold finish—all of which impact the price.
How Many Processes?
Do you know what the minimum number of processes a multilayer PCB goes through from start to finish? Twenty eight—and that is the minimum! I have posted a chart below that shows each process (in order) that a multilayer PCB goes through. Now mind you, if a fabricator makes a mistake at any one of these processes—the boards head for the scrap pile along with their profits. All these steps are the building blocks to make a successful board that will enable networks of connectivity to hum. First, however, these boards must withstand a great deal of heat and mechanical stress during assembly before being expected to persevere through many hours of run time and enabling those amazing components to sing and do their magic. Yup…wind beneath their wings, indeed!
In part two of this blog series I will discuss cost vs. value of today’s PCB. Meanwhile here are a few links I thought you may enjoy taking a look at:
PCB Industry Timeline:
Making of a four Layer PCB (Video):
How a printed circuit board is made:
It is always both helpful and encouraging to hear from you! I welcome your comments below or you may email me directly at Judy@Translinetech.com. Feel free to visit the Transline Website for helpful industry resources as well at www.Translinetech.com. Best wishes!