The Learning Curve

Looking back over the last few months, I realize this should have been my first post on the subject of DPCB. At least it should be the first post you read if you are not already doing DPCB.

Do NOT expect that you can buy a machine and product double-sided boards for 0402 surface mount parts! You have a lot to learn first.

There is just too much stuff that can not be put into the instruction manual. Most importantly, learning from our mistakes.

For example, when you have finished printing the conductor, it is wet, soft, and easy to destroy until it is baked. To bake it, we need to unclamp the board and then re-arrange things so the board is 'upside down' and ready to bake. It is in the process of 'flipping' the board that I have already a few times, destroyed my print.

Like my father, the safety engineer said "by the time you poke out a couple eyeballs, you start to learn."

Here are a few simplified suggestions:

  • Start with disposable nozzles. They are harder to break and cost 1/20 as much as the very delicate steel nozzles.
  • Start with nothing smaller than 0805 SMD. I would like to suggest 1208 or 1812 until you have made some of these mistakes.
  • Set your pcb design software rules for extraordinary conservatism. Clearance of 16 or 18 millinch. Trace width of at least 12 millinch
  • Ink is expensive! But not as expensive as time. If you have a flaw, just wipe the substrate clean and print again.
  • Keep a notebook. Jot down things like ink dispenser settings for disposable nozzle versus the metal nozzles, your reflow temperture and times.
  • Add fiducials
  • NO VIAS under components.

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