Idea: Silkscreen for Manufacturing and Part Numbering

So… I had this question come up in the back of my mind…

My design with have different stages of assembly.

  1. Bare board
  2. Board populated by SMD assembly.
  3. Board populated by hand soldering and final finished product.

The idea is to have 3 different part numbers on the board.
One under a SMD part.
One under a hand soldered part.
One that will always be visible.


Anyone have an idea how much confusion this is going to cause the different manufactures?

Good idea, or bad idea?

I’ll have this board in hand in about a week and I’ll walk into a well known manufacturer and post their feedback then. In between now and then I’d like to know what you think about my idea.


  1. Bare PCB just has text on silk screen. Can’t think of a reason for problems.
  2. SMD Assembly needs a placement file & which part goes where. It’s just computer data and it should not matter as long as there are no duplicates in names.
  3. Hand soldering & finishing. KiCad’s Fab layers are meant for this. You can place notes there for hand soldering and assembly. This is not “computer data” but meant to be printed on paper (viewed on monitor) and interpreted by humans. You can put whatever notes you like on it.

Alternatively, there is a very nice project (although I have not used it myself) that aids in hand assembly:

From the middle of this video you can get a good idea of what it can do:

@paulvdh Good information.

I obviously did not convey the idea of my concept to you. For obvious reasons I don’t want to share the entire board information on the interwebs; the reasons for the small screen-grabs in the OP. Tomorrow I will upload a dummy example that more clearly shows the concept I had in mind.

I’ve got a weird brain that always attempt do delude me when interpreting communication with other people.

If it’s just about your part numbers (all on Silk screen I assume)

  1. Under SMD. Nobody will see them. The machines don’t care.
  2. Under THT components. This can help during manual soldering.
  3. Always visible. Sure, do what you want.

There are other simple tricks that help with manufacture ability. For example when THT electrolytic capacitors are used I always put them all in the same orientation, even if it makes PCB routing more difficult. If you have two values of electrolytic capacitors, then try to use different pitch for the pins.

Similar for THT LED’s, (even for round LED’s) Orientation is always the same for all LED’s. If you have to look up for each LED whether the long leg goes on the top, bottom, right or left, then it is a lot easier to make mistakes.

The Japanese call this:

[Edit] “elco” -> electrolytic capacitor.

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Just label the pn:
Assembly level 1 (Assy1)
Assembly level 2 (Assy2)

I worked at a big company which had pn for various levels. They had a group of numbers reserved for each level so you could read the number and know the level.

You also should create a drawing of each level to define the BOM at each level.

Look up Configuration Management on the web.

How about putting a certain selection of text “upside down” (rotated) on the PCB, compared to another set of text?

Now you’ve captured my curiosity–What is an elco ?

Common Dutch name for Electrolytic Capacitor.

Hi Sprig,

It is not a good idea to have different part numbers for different assembly stages. It is recommended to have a single part number for a single board.

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