Issue link: https://iconnect007.uberflip.com/i/1512857
12 DESIGN007 MAGAZINE I DECEMBER 2023 rotations. But the pads were no longer where you could route cleanly into them at the 90- or 45-degrees with standard inter- active routing or autorouting because we were doing all these oddball route angles. Shaughnessy: Is this something you cover in your class? Moyer: Here's something from my "PCB Design for Advanced Design Concepts" class. Imagine a circular board with a doughnut hole right where a rotary sha has to go through the center, and all the parts are out from the center. Now, imagine trying to route using standard routing out from, say, the 3 o'clock position around. I don't know of any routers that will do a continuous sweeping arc. Yes, you can do 90- or 45-degree rounded corners with ECAD routers, but they're still trying to draw a straight line. In a circular board, the better routing plan is to just do a continuous arc. I can get the router in 3D modeling tools to do this. But in ECAD tools, I can't say, "I want to start at this point, and I want to follow a continuous arc all the way around, get back into my part, moving from 3 o'clock counterclockwise around to 9 o'clock to make a connection there." Since it's a circular board with a doughnut hole, I can't just go to the center. at's another big chal- lenge you will run into with oeat shapes. ere's also still a population of board designers who don't know how to import IDF, DXF, or STEP geometries from an MCAD tool. ey're used to going to their ECAD tool, drawing a rectangle, and making it their board. at's one of the big things right off the bat is to let the designers know this capability exists, and you might need to know how to import from an MCAD tool into your ECAD tool to set your geometry shapes. With most of our modern soware tools, from the "Big ree" EDA companies at least, you can import the 3D STEP model directly and say, "Make that the shape of my board," without needing to go through the intermediary 2D formats of IDF and DXF. All my 3D work is in STEP and I don't have much need for IDF. But the entire design commu- nity should know how to work with these various importable MCAD geometries. Kelly, what are your thoughts on this? Kelly Dack: is is a good dis- cussion because we're com- ing from different ends of the industry. You're coming from the very complex aerospace and defense end of design, and I work with the very normal, producible volume types of products. I agree with your comments about how rout- ing and component placement is affected by outline geometry, and the way it affects how we address everything within those outlines. I'm coming from the perspective of design for manufacturability because what you're talking about is getting all that copper topology to fit within an outline. As Kris mentioned, many designers don't know how to import MCAD files. Could you use your ECAD soware to replicate a geomet- ric shape defined by your mechanical counter- parts? Impossible. So, we have to rely on DXF, STEP, and IDF. Designers need to understand these other file formats, which are really lan- guages. How do we process board outlines that are even crazier than circular boards? I came from a gaming company that builds slot machines. I designed LED boards that would fit in these things called "toppers" that sit on top of the game, and the LEDs light up to attract people to the game. I've created boards that are in the shape of Batman. I also designed a board in the shape of Frank Sinatra's signature—a strip of cursive writing with LEDs all over the place. So, we can both agree that anything can Kris Moyer