PCB Component Silkscreen Distance

[JRJJ]

  Hi friends, I am trying to build my own library of components in Altium Designer and came across an issue with the distance between silkscreen and pads. I have tried finding any IPC or any kind of related standards that mention the silkscreen distance from the copper pads but, I could not find any definitive distance. Some searches I have found mentions like this:-

"The silkscreen needs to have a distance of 3-6Mil from the solder mask window pad," (https://www.pcbaaa.com/pcb-silkscreen/)

"The minumum distance between a pad and silkscreen is 0.127mm." (https://community.aisler.net/t/silkscreen-specification/2192)

"It is recommended to keep a minimum distance of 0.5mm between silkscreen and pads/traces." (https://hillmancurtis.com/silkscreen-altium/)

"0.01″ (10mils) is a good general number for spacing between silk and copper to prevent issues." (https://www.macrofab.com/blog/handling-silkscreen-pads/)

"keep the component outlines away from the pins, at least at a distance of 0.25mm" (https://powertransformersindia.wordpress.com/2019/06/17/pcb-silkscreen-what-is-it-miracle-electronics/)

1. I am trying to obtain a clearly defined silkscreen that does not get hidden under the physical component on the pcb.
2. I would like to know is the silkscreen distance between the copper pad and silkscreen or is it solder mask opening to silkscreen?

I hope someone could generally provide a suitable distance value either based on their own design experience or if someone could point out to a standard somewhere I missed out. I appreciate all your help on this matter. Thank you.

[tooki]

You won’t find a “definitive distance” because it varies by PCB production method and manufacturer’s preference.

Look at what your preferred PCB manufacturer wants and do that.

[Jwillis]

Sometimes the units used to describe the distances can be confusing. If your not aware, #Mils is an SAE unit and not millimetres which is of course metric. Just wanted to clarify that first. When it comes to silk screening, theirs really no rules carved in stone. It comes down to the amount of space available. Silks should have enough space from the pads to prevent coverage during production as there may be some deviation. So 0.5mm sounds pretty good. Silk references should be legible so .6mm height is probably a good lower limit.
On Kicad the Silks are just outside the Fabrication lines. The fabrication lines are the actual dimensions of the component and aren't usually printed.
When references are used, either the component number is used or the value but never both.
References should be the same orientation.
In areas where many components are clustered together, the references  can be listed in another location where there is space as long as the list closely represents the location of each component in the cluster.
If there is no space for any silk printing then it's permissible to omit completely.
Again theirs no gospel rules, but its always a good idea to consult the fabricator about any possible limitations of the equipment they are using.
 

[Solder_Junkie]

If you check the YouTube tour of JLCPCB, you will find that some boards are printed using “inkjet” printing, not silkscreen.

As mentioned in the last post, you do not need to label/outline everything. With tightly spaced parts, you may just outline some parts for orientation purposes and keep a more detailed printed layout as a reference.

This Chinese manufactured GPS board is a good example where not everything is labelled or outlined.

SJ

[tooki]

Oh yeah, I meant to mention: Altium 23.0 introduced the new Silkscreen Preparation feature, which lets you clip silkscreen that’s too close to pads, without requiring you to modify footprints.

Altium 23.0 release notes

[liaifat85]

Many designers recommend a distance between 3-6 mils (0.0762mm to 0.1524mm) from the copper pad to the silkscreen. This helps prevent the silkscreen from being hidden under the physical component.