Reading time ( words)
Star Date 1978
“Change is the essential process of all existence.” - Science Officer Spock
In a cold (62°F), semi-dark room, there are banks of mainframe computers along one wall; a soft light glows upward from the table in the corner. I take my kit—a variety of sizes of black, red, and blue tape, decals, and an X-Acto knife—and set it on the side table. On the top edge of the light table is a bar with pegs spaced about eight inches apart. A sheet of Mylar imprinted with a 1/10th-inch grid is fitted over the pegs and taped down in the corners so it won’t move. On top of this are two sheets of clear Mylar—one for the two sides of traces and one for the pad master of the circuit board I’m creating. Later, I’ll add another sheet for all the reference designators and part outlines. I have some decals for those, too.
This is the first board I get to do myself from start to finish. I’ve been apprenticing for three years now. I’ve been drawing all the schematics from napkins and scraps of notepaper from the engineers, creating the sepias for the fabrication and assembly drawings, and being the gofer running all the files around to the photoshop and fab house. I have an engineer-approved schematic and I’ve made a rough sketch of where I want to place each part and the connections between them. Today, I start placing the decals and tape.
I have to wear a warm jacket and hat in this room as I carefully place each component decal (most are 14-pin DIPs, resistors, caps, and a few transistor cans) on the intersections of the grid lines and carefully align them to each other. Once I put them down, I don’t want to move them as they won’t stick so well then. This layout will be the typical 4:1 scale, so I need to place my targets outside the board for the photographer to sight on when they reduce the artwork. This is how we’ve been doing PCBs since the ‘60s.
Star Date 1988
"We prefer to help ourselves. We make mistakes, but we're human—and maybe that's the word that best explains us." - Captain James T. Kirk
Now in the late 1980s, there’s this new method for designing PCBs. I’ve looked at it. It’s a new software program called OrCAD that lets me export this file—ASCII, I believe—that has all the connections from the schematic, and then import this to the graphic layout portion of the program. This is a great time-saver, especially for doing the schematics and pre-sketch of my boards. It’s a little slow on my new 286 computer because it uses a lot more memory space than AutoCAD does. Also, I can’t get a good printout with the dot matrix printers for our photographers. The image is too grainy, even when reduced. Guess I’ll still need to do a tape-up of the boards. Glad I got my EET degree, though, as these layouts are getting tougher. I keep getting asked if I know how to do a twisted pair on a circuit board. Don’t know if that’s even possible yet. And it would take up a lot of real estate to do something like that.
Finally! We got new inkjet plotters that create an image that can be photographically reduced. It’s a bit of a slow method and we have to run the plotter overnight for some of the larger jobs. When no one is around, unfortunate events will happen. One design got totally stuck printing one hole pad many times over and made a mess of the plotter. Have to be careful not to put down multiple pads in one location as those plotters are expensive. But it sure makes great plots of schematics, and doing changes to the design are much easier now.
To read this entire article, which appeared in the June 2021 issue of Design007 Magazine, click here.