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We’ve seen many changes over the past few years, and nowhere are they more evident than in the world of sourcing components. Sourcing has become one of the biggest challenges facing PCB designers and design engineers today. Gone are the days of procuring parts from a single source, and communication between stakeholders and distributors is critical.
But as we learned in a conversation with I-Connect007 columnist Kelly Dack, an EPTAC design instructor and PCB design team leader at an assembly provider in the Pacific Northwest, PCB designers can use certain layout strategies to plan for the unexpected, such as leaving extra real estate so that smaller components can be replaced by larger, readily available parts if the originals become “unobtainium.”
Here, Kelly discusses some timely sourcing ideas, why he believes industrial engineers should be involved in “right-sizing” the PCB, and why sourcing efforts must also focus on recruiting—or creating—PCB designers.
Andy Shaughnessy: Kelly, you’ve been involved with DFA issues for years. Why don’t you talk about some of the challenges you see with sourcing?
Kelly Dack: Sure. The problems we see are projects that begin as traditional projects. We have customers who come to us much like on “Shark Tank.” There’s an idea, some seed research and development has been done, the results are favorable, and they want to take the product to production. At that point, we evaluate the product to determine its feasibility for meeting the capabilities of our assembly lines. Everything is fine, just like it always is—until it’s not. That’s because with today’s rusty, knotted supply chain we are not able to source certain components. That one little thing can slow down or stop the entire project. We limp along until we can either change the design, modify it so that we can find an alternative component, or redesign the circuit so that we can use alternate components that will do the same thing.
Happy Holden: You understand design for manufacturing. Now we’re not talking about process capability; we’re talking about part availability, but that’s still manufacturing.
Dack: That is still manufacturing and sourcing, and that plays into it, Happy. A product can be totally 100% designed and look very good from a production standpoint and from a DFM standpoint. But now, when a part suddenly becomes unavailable, it could require another part to be designed in, which may not be form-fit and functionally the same, but it could still work. But now designing in this part has to be done properly so that design for manufacturability is considered. How many parts do you have to nudge? What’s the domino effect if we do manage to fit this part in?
Holden: So, we have to make a change in design so that the information is known up front and it’s not a do-over?
Dack: The problem we’re finding is that everybody is using the smaller parts, and the large parts are left over. So, if you want to find an equivalent functional part, chances are all the tiny ones have all been gobbled up, and you must be willing to buy the larger-scale parts. But how do you fit the larger-scale parts into your layout?
Shaughnessy: There are those dominoes, right?
Dack: Right. Let’s take a step back. During the shrinkage era in the ‘90s, when we were working on iterating boards down as small as they could be, I coined the term “practical packaging density plus.” The idea is that we determine an appropriate packaging density, and then once you get that dialed in, what’s wrong with adding just a little more for future design purposes or manufacturing purposes? Why do we constantly design to the minimum, tightest density?
Shaughnessy: Are you talking about adding more real estate?
Dack: It can be real estate. Packaging density has to do with the amount of real estate on a given PCB vs. the components and everything else, and all the geometries involved with the components.
To read this entire conversation, which appeared in the September 2022 issue of Design007 Magazine, click here.