After some hangups with USPS, the new boards are finally built and assembled as of last night. Photos updated to reflect reality.
The value of a stencil
With as many fine pads as this board has, the first few units took me about 1.5 hours each to assemble. Of that, most of the time was spent painting solder paste onto pads. I ordered a stencil for this one, and measured assembly time last night.
Linear time costs (paid once per board with or without stencil):
- 10 minutes to place parts under the microscope
- 1 minute to bake and cool
- 1 minute to inspect soldered board
- 1 minute to clean the board after soldering
- 1 minute to test on debug jig
The step costs that differ with a stencil are...
- 2 minutes for jig setup with a blank board, stencil aligned and clipped into place
- 3 minutes to spread the paste
- 1 minute to remove the board and inspect the paste application
Constant time costs (paid once for each assembly session):
- 2 minutes to setup
- 8 minutes to dispense the needed parts from stock
- 2 minutes to clean up
Lesson learned: I figure the stencil saves about 130 minutes per board, and gives far cleaner results, besides. Highly recommended, even for assembly of one unit of this pad count.