solder mask error on imported ring pad polygon

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krowmostow5
Posts: 2
Joined: 20 Jan 2021, 12:45

solder mask error on imported ring pad polygon

#1 Post by krowmostow5 » 03 Feb 2021, 19:28

I'm running into an issue when I go to create a simple surface (non through hole) ring pad for the outer contact of a tactile dome switch. I create 2 circles in a CAD program and import them as a DXF. I choose add, fill, and embedded polygon options, top signal, to import and then convert to a pad. That part works great. I can use it in a board outline and connect to it with no issues. I basically use the instructions I that others have mentions for annular rings.

The issue is a voided segment area gets generated in the solder mask. You can see it in the Gerber files. Basically it creates a small void in the solder mask keep out area and allows a thin line of masking applied to the ring. This line is at the exact same point where diptrace jumps from the outer points of the polygon to the inner points. Almost like it looks at it like a long rectangle that is curved around a center with the ends butted together instead of a whole ring. And the thin line of masking it right where it butts the end together.

Has anyone else seen the same thing??

Tomg
Expert
Posts: 1650
Joined: 20 Jun 2015, 14:39

Re: solder mask error on imported ring pad polygon

#2 Post by Tomg » 08 Feb 2021, 08:39

I created a twin-circle DXF file using Alibre Design. After importing into the Pattern Editor and converting to a pad I can see a Paste Mask gap, but no Solder Mask gap. However, the Solder Mask does cover the entire pad...
smd_void.png
Placing the pad into a PCB and previewing the Gerber shows the same thing; a "C" shaped Paste Mask and a Solder Mask that covers everything...
gerber.png
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Tom

Alex
Technical Support
Posts: 3429
Joined: 14 Jun 2010, 06:43

Re: solder mask error on imported ring pad polygon

#3 Post by Alex » 08 Feb 2021, 10:22

You can open "Mask/Paste Settings" of the pad and disable mask and paste generated by default (change solder mask to tented and paste mask to no solder). Place custom shapes on mask and paste layers correspondingly. A circle with appropriate width on top mask layer and one more circle on top paste layer will be OK.

krowmostow5
Posts: 2
Joined: 20 Jan 2021, 12:45

Re: solder mask error on imported ring pad polygon

#4 Post by krowmostow5 » 12 Feb 2021, 18:41

I use TurboCad to make my DXF and seems to have a different but similar outcome. I attached some pictures of what it looks like as I drag it from my library, what it looks like laid down, and what the gerber preview of the mask looks like. The paste on mine is the mask. There gap like what you have with your paste, but appears on both my mask and my paste and coincides directly with how Diptrace increments through the points list. I can work around it, I just wanted to see if anyone was running into a similar issue.

Thanks for the Response!
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