Sunstone’s Matt Stevenson Shares Insights From New PCB Design Book

Estimated reading time: 3 minutes

There’s designing the “perfect” circuit board and then there’s designing a board that is “perfect for manufacturing.” While seasoned designers and design engineers understand many of the nuances, PCB fabricator Sunstone Circuits has just published a new book specifically for new designers who have the knowledge of design but are still learning what it means to get the board manufactured. Sunstone’s Matt Stevenson takes the reader through a series of situations that should help clarify what’s happening in the fabrication process and how to adjust a board design to be better suited for manufacturing. 

Johnson: Matt, I understand Sunstone’s got a new eBook just ready to publish. Tell us about it.

Stevenson: You are correct. The book is called, The Printed Circuit Designer’s Guide to… Designing for Reality.

Johnson: That’s a compelling topic, and very pragmatic. Tell me about what a reader can expect to learn.

Stevenson: We envision the book as a summary: hit some of the hottest topics for design engineers to consider while designing their board from a manufacturing standpoint. Process tolerances, process variations and how that affects designs, and how designs can be done such that it doesn’t exacerbate any of the tolerances and manufacturing process windows.

Johnson: Those considerations are not always clear to somebody who’s working in design but hasn’t experienced the physical manufacture–that it is a somewhat imprecise process. You have to do some give-and-take to get the precision in manufacturing that often is required by the designer.

Stevenson: Right. There are a lot of variables in a PCB manufacturing facility. Chemical processes, mechanical processes, environmental factors, material movements. Those things can all come into play when manufacturing a circuit board.

Johnson: And if a designer can account for those considerations, that helps set things up for you to deliver greater yield and precision?

Stevenson: Exactly. I always like to tell new designers to come visit a circuit board shop so you can see firsthand some of those real-life applications of chemical and physical processes, how there are limitations, and how design can make the results worse or less manufacturable, and also, less reliable down the road. In the book, we really try to give you all the tips and tricks for highest-yield designs and highest-reliability design.

Johnson: Give me a couple of examples of things to consider from the book. 

Stevenson: One of the most critical is fluid movement within a through-via: trying to get the electroless copper in and out of a via with sufficient timing to get the thickness so that you get a good metallization throughout the hole. The thicker the panel, the smaller the hole, the harder it becomes from a physics standpoint to get plating solution to move uniformly through the via. You’re relying more on capillary action rather than actual fluid movement.

Johnson: That’s a great example because, in the design tool, the designer is looking at that as a perfect cylinder, right? Designers see it as a perfect hollow cylinder through the board, but the reality?

Stevenson: It’s never perfect. Think of it as rifling from the drill bit. There’s a lot of topography inside that hole between glass and epoxy, lots of different types of materials inside that hole. It definitely is not smooth. It almost acts like Velcro for air bubbles inside that hole.

Johnson: Considerations such as this are what you’re bringing to the forefront in your book?

Stevenson: Yes! We try and give as many tips as we can.

Johnson: Who do you see as the ideal target reader?

Stevenson: The beginner and new PCB designers will get the most from it, but even seasoned designers will find “ah-ha” moments.  

Johnson: Sounds like think this will be a great resource for any designer looking to make the best decisions to save time and money.

Stevenson: It’s something that we’ve been passionate about for a long. Our hope is that it is well received, and we can do a follow-up.

Johnson: Terrific. Matt, thanks for taking the time to talk.

Stevenson: Thank you, Nolan.

To download The Printed Circuit Designer’s Guide to… Designing for Reality, click here.

To visit the I-007 eBooks Library, click here.