Solder mask clarification


#1

Hello,
I’m trying to understand how the solder mask works.
I have the attached part. The 2 long pads at the bottom are for soldering cables on them, so they shouldn’t be covered in solder mask (right?). However I’d like the other part of the paths to be covered by solder mask. I’m not sure how to do this? How do I create a solder mask over the parts that I’m interested in covering? I see that there’s a solder mask for the JST holes (came with the footprint I guess?).
Thank you!


#2

Edit the footprint of the 2 long pads. In the pad properties, check the solder mask box.
Then, the two pads will not be covered by solder while the tracks to the connector will.

See also How does solder mask layer work?


#3

hi, thank you. I don’t see the “solder mask box” you mention. Is it in the footprint properties window (double click on the pad)? I see I can change clearance here (under Local Clearance and Settings) but the 3d model still displays the same…

the 3d model with mask looks like this


#4

Quick option: post your full project folder as a zip archive. (you might need to put it on some cloud service like google drive or dropbox and link to it as i am not sure new forum users can upload files)
Or at least the pcb file.


Are the things you want to use as solder points part of a footprint or are these simply traces?
If they are part of a footprint then i would assume they are smd pads. Every pad has a properties menu. In it you can select F.Mask (assuming the pad is on F.Cu)
If you used traces then i suggest you make a footprint using pads.


You might want to look at these FAQ articles:


#5

It is in the pad properties, double click on the pad.
By the way, which Kicad version are you using?


#6

Maybe you need to tweak the 3d display options and check show solder mask layers.


#7

Hi all,
thanks for all the replies!

I’m using latest kicad version (5.1.4) for Mac. Attached zip file. The part is SMD…I’ve managed to change something but I still don’t fully get it since I don’t understand what it should look like in the 3d model.
Thanks a lot!

pcb.zip (79.6 KB)


#8

I just updated the FAQ article How does solder mask layer work?. Maybe it helps you.


#9

thanks! that’s clearer now, I think I’m getting there. If it’s correct, now I should have the 2 round pads uncovered by the mask (I guess that’s why they’re red in the 3d view).
However it looks like the rectangle between them is still covered and if I double click on it (to access the properties) I can only edit the line thickness. How do I make sure that polygon is also excluded from the mask?


#10

Why did you choose the net-tie footprint? That one is meant for a very special (advanced) usecase. Use one from the connector_wire lib. The only SMD one is SolderWirePad_1x01_SMD_5x10mm but you can copy that one to your personal lib and change the size of the pad to fit your needs.


#11

hi, I chose that footprint because I need a bigger pad to solder a cable, without any hole. Would you recommend better footprint? thanks


#12

thanks, I looked at the one you suggested and changed the size! It looks perfect now!

Thank you a lot everyone!