Author Topic: Silkscreening the part reference inside or next to pads?  (Read 753 times)

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Offline profdc9Topic starter

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Silkscreening the part reference inside or next to pads?
« on: September 03, 2019, 02:13:41 am »
So I have been designing PCBs, and when I have a through-hole part, I have been placing the part reference inside the box that joins the pads to denote, for example, the terminals of a resistor or capacitor.  I do this so that the references don't take extra space and therefore try to keep the PCBs small and costs down.  However, it means that after the part is installed, the reference is covered by the part, and a map of the PCB which shows the references needs to be used to find where a referenced part is.

On the other hand, the reference could be placed next to the pads, and not inside the box joining the pads, so that installing the part does not cover the reference.  The problem I have found is that if you have a high density of parts, it's not always obvious which reference goes along with which part.  Then the parts need to be separated even more so that it is clear which reference is associated with each part.

So any opinions around here about if it is too much trouble, or too error prone, to require someone maintaining a board where the components cover the references to use a map to find the references?
 

Offline Etesla

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Re: Silkscreening the part reference inside or next to pads?
« Reply #1 on: September 03, 2019, 02:32:22 am »
Generally, especially with SMD components, res defs go next to the part. I have hand soldered and done repairs on a lot of dense SMD and THT boards. The most useful thing for me is when the person who made the PCB uses an easily interpreted pattern across the whole board, like only having res defs rotated in two of the four possible rotations, or only putting the res def parallel to the long axis of passive components. Recently, I have been working in KiCAD and using the 'interactive BOM' tool. It serves as my 'map' when I'm soldering and troubleshooting. I believe the file generated by interactive BOM can be handed off people without the KiCAD files as well, but I haven't tested this. In short, look into the interactive BOM tool for your mapping needs and switch to KiCAD asap if you're not already using it:) (I am a fanboy)
 

Offline profdc9Topic starter

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Re: Silkscreening the part reference inside or next to pads?
« Reply #2 on: September 03, 2019, 03:06:41 am »
I already use Kicad for most of my projects, you can see them at http://github.com/profdc9

For example, this is a board I've made.  I have two versions, a through-hole and SMT version for kit builders:





The SMT one has the labels next to the parts, because they're small, but the through hole one has bigger parts so I put the reference inside the part box.

Perhaps this is a bad idea?  I'm trying to keep the size of the PCB smaller as to keep it an economical kit.

 


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