A few years ago we purchased some “panelized” circuit boards of the Blinky Grid SMT design, which means that there are several copies (16 in this case) of the same circuit board design connected together in a snap-apart panel. This makes it easier (and quicker!) to assemble the boards in bulk.
The first step in bulk assembly is to apply solderpaste to all the exposed pads on the circuit board. We purchased a stainless steel stencil that matches the 16-board panels, then used a squeegee to apply lead-free solder paste through the holes in the stencil.
After all the pads have solder paste, the next step is to place each part on the board, stuck down into the solder paste. To place the parts, we use a machine called a Pick-‘n-Place (PnP). This is a desktop computer-controlled robot with a small vacuum nozzle that can pick up a part, optionally rotate it, and place it down in a precise location on the circuit board. Here’s a two-minute video of the PnP machine in action:
After the parts have been placed on the board, we need to heat it up to melt the solder to attach the parts. We use a small soldering oven to do this.
After the boards have been baked, the solder has melted and connected all the parts to the circuit board. The remaining steps include:
Solder the through-hole parts, like the pushbutton and sensors
Program the microcontroller with the Blinky Grid program code
Test that everything works correctly, including programming
Wayne and Layne, LLC makes custom interactive installations and open source hardware. Our kits come with easy-to-follow illustrated instructions and explanations of how the kit works. All the schematics, PCB artwork, and source code are provided under open licenses.