Hi all,
I am just new into this forum. So thanks all.
I just tried my pcb here and I have some issues with soldermask in bottom later.
When sending my pcb to the factory, they say there is no soldermask layer. Even if I check into online gerber file I see no bottom soldermask, so the cooper is exposed.
I checked the board setup, soldermask is thicked, and I see the soldermask in 3D viewer, but not in the manufaturer or gerber viewer.
There is no components in bottom side, just a cooper plane, vias, soldermask(nothing as it is negative) and silkscreen.
Any tip will be welcome!?
draw a simple small object (line/circle) on the bottom soldermask layer. Then the soldermask layer is not completely empty and you will get a valid gerber file.
Did you also tick B.Mask in the Plot menu when generating the gerbers? You should have a file called project-B_Mask.gbr among the gerber files.
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yes, I thiked the b.mask in the Plot menu.
It happens only in the projects I start with Kicad 8.0.7, because I try old projects and it works. I am working with Kicad 8.0.7 in ubuntu 22.04
I also tried to add a line into b.mask, see it into this screenshot in 3D view (where I see the PCB properly)
I forgot the 3D view from Kicad, my fault: This is the bottom side, see in left top, the small line is in the b.mask layer. see here:
even I added this line, I found problems with the manufacturer and they told there is no b.mask layer. I can check with PCB Way or eurocircuits as other online manufaturers.
Many thanks in advance!
I just discovered if there is no component or track on the bottom side, then the bottom side is not properly defined. I just changed a component to botom side and then it’s ok.
In my pcb there is bias to the bottom as this is a ground plane, in this case the gerber b.mask is not properly generated. If I change a component, then it’s ok.
(?)
Thanks in advance!
In my pcb there is bias to the bottom as this is a ground plane, in this case the gerber b.mask is not properly generated. If I change a component, then it’s ok.
If you have nothing on the bottom side then you will get a nearly empty gerber file for bottom solder mask: the file contains only the gerber header lines, but no aperture list and no items.
Some gerber viewers (and some pcb manufacturers) seem to have a problem with this.
The solution is to place a dummy item on the bottom solder layer. As you discovered a flipped footprint works, but the simple line (from my first answer, and shown in your 3D-picture) should also work to get a filled gerber file for bottom.mask layer.
I don’t know why the “simple line” approach doesn’t works in your case (maybe line-width too thin? Do you have a value defined for board setup–>solder mask&Paste–>solder mask minimum web width?)
Thanks for all the answers.
This is a very simple PCB, with just few components. I readed the @eelik link and all documentation, and I did some research as well before asking here.
If I flip the any component, then it’s ok, but if there is no components, then it doesn’t work.
I tried the idea of a simple line into b.mask layer, and checked the solder mask minimum web widh to 0.1mm. but always is the same issue.
To solve it I just added a dumy smd component outside the PCB edges, and then it works.
You could take advantage of the need for something in the soldermask by putting some text or logo on the mask layer. That will end up being visible as HASL, if that’s your chosen finish, so you get silver text or logo.