Join Kipp Bradford for an in-depth discussion in this video Electronic circuit boards, part of Skilled Trades: Manufacturing Careers.
- So you might be wondering how electronics get manufactured. Well, I'm going to show you. I've got a circuit board right here, and this circuit board needs to have these components placed on it and soldered down. Now, I've taken the components and I've printed out the actual design that I created on the computer, and I'm going to tweezer each of these components onto the corresponding place on the circuit board. In order for the components to get soldered down, I have to apply solder to the board itself. In this case, I've got a nifty little contraption here that is a solder stencil with apertures that match each of the locations that I need to place the components on the board, so I'm going to slide the board here onto the stencil, and I'm going to take solder paste that is in a paste format, which is much easier to apply using this little squeegee here, and I'm simply going to squeegee the solder paste through the holes in my stencil, and now, when I take the board off the stencil, there's solder on each of the pads where I need to place the component. Each one of the parts that I've placed on my sheet of paper needs to be carefully and precisely located on the circuit board. So, when you design a circuit board, there are two parts of the design. There's the schematic file, and there's the layout. The schematic file lets you work on what the logical connections are, so it helps you see what parts are going to get connected to what, and then the layout lets you physically place the components in space with those connections already wired up. You do have to create the actual pathways that each electrical signal's going to take, and once you do that, you can send your circuit board design, the layout file here, off to a circuit board fabricator, where this fiberglass board will get manufactured. Of course, that circuit board manufacturer will send me this bare board and I still have work to do. That work is what I'm doing right now, where I'm placing the components on the correct location on the board. And now, I've got all the parts properly located on the circuit board, they're stuck down with the solder paste that I've used, which is sticky enough that the parts don't slide off, and I'm ready to put this into a reflow oven so that we can bake all of the binder out of the solder paste, the solder paste will melt, and then cool, and that will create a metal bond between the component pins, which are metal, and the copper and gold-covered pads on the circuit board, and I'll have a functional circuit. I do use a toaster oven sometimes, but in this case, I actually have a real reflow oven, going to turn the oven on, and what I end up with is a fully-soldered circuit board at the end of that process, so I can remove this, I've let it cool for a few minutes, and take it out, it's still a little bit warm, we're going to go ahead and turn off my reflow oven, and what you see here is now these components are bonded fully to the circuit board, so the solder paste has heated up, it's melted, and now it's cooled and I have a metal-to-metal connection between each of these components here and the circuit board itself. The circuit board I have here, I have placed all the components by hand. It's a slow, it's tedious process, and it means that this component becomes pretty expensive. Now, modern manufacturing allows me to make many multiples of this circuit board quickly, efficiently, cost-effectively, but that's only possible because there's a human who has to program the exact actions of the robot to make sure that each of these components is placed properly and accurately, so all of this comes down to a skilled machinist who's operating a robot that's moving X-Y, picking up parts in Z, moving them, and then placing them on each of these locations. None of our model electronics would be possible without the machinists who are operating the pick-and-place robots in electronics manufacturing.