I am working on a Clamp Filter for a system we are designing, and i need some assistance with the software. This is my first time using KiCad, and as such am unfamiliar with terminology and menus, so if you could provide directions with your pointers, that would be wonderful.
When I run DRC, I get 23 Errors involving the Front Solder Mask and I am unsure of how to rectify this. All footprints are default to the Library (No Custom), which should imply that they are properly set up.
Can anyone please review the errors below, and let me know how I would fix this?
Error: Front solder mask aperture bridges items with different nets
Track [< no net>] on F.Cu, length 3.000 mm
PTH pad 1 [< no net>] of MOV
Thanks for reaching out. Is there a way I can show you the full project?
I am using KiCad 9.0.2 Release Build
I did not make a schematic first, I simply went to board design. I drafted the Schematic manually. (pen and paper) I was unaware you couldn’t do it that way.
When IC pads are very close to each other there is not enough room between them for even a very thin solder mask strip. Depending of technology requirements it can start from pitches 0.5mm and smaller.
There are settings for minimum solder mask margin (depending on accuracy of positioning mask) and minimum mask strip.
Classical was 4 mils and 4 mils. For many years I was using 3 mils and 3 mils. In KiCad I have set it to 0.075mm and 0.075mm. So the distance between pads I need is 0.225mm.
For 0.4mm pitch and 0.2mm pads the distance is 0.2mm what is not enough and such IC pads get common solder mask opening and it is what KiCad tells you (each pad has different net and they are in the same solder mask opening).
Should not be, provided you don’t have some very unusual settings.
It is hard to me to be very precise as since half of year I’m busy with something else and not using KiCad at all.
The Error mean that you have a track with no net connected to a pad.
If you don’t have a schematic, the DRC will not work.
Kicad cannot check which track and which pad are supposed to be connected or not connected.
So if you directly draw a PCB without doing a schematic first, then you will not be able to use the DRC checks to validate your work.
I’ve just missed that message you were writing at the same time I was writing my answers to your first post (I have also forgot there exists people trying to design PCB without schematic).
This explains your problems. KiCad gets nets from schematic. I even don’t know what happens with track and pad nets when you have no schematic (never tried it).
When you connect track having different net to pad (you can do it for example in Highlight collisions mode) then in solder mask opening for pad there is also track having different net so you get message that in one opening there are different nets.
That is unfortunate that it requires both models for such little reason, when the program could easily be made to not require this.
So i have to re-build it in schematic first, then redraw the PCB if I am not mistaken? or if I know that the tracking is done right, (1 layer PCB) then it should be okay to continue and ignore them as false positives?
Since you managed to make a PCB then apparently it is possible.
DRC task it to check if PCB is made according to schematic (connections made at schematic are also made at PCB and no extra connections are done).
I use standard clearance of 0.2mm, but for 24V tracks I set clearance to 0.4mm (I do it by assigning (at schematic) all 24V nets (few nets going from supply input through fuse, ferryte bead and diode to regulator) to net class I name HiV. Then DRC checks for me if specified clearances are preserved.
Working without schematic you give up 80…90% od help you can get from KiCad. There is no point in improving such a senseless use of the program. If you have no schematic then there is little idea in running DRC at all. But if you want to run it than you should ignore errors coming from having no schematic. Having track with different net being connected with pad with different net is just one of consequences of having no schematic.
Imagine what DRC should do if you have two copper elements (tracks, pads, vias) with different net very close to each other. Having no schematic DRC don’t knows if they should be connected so there is lacking connection here or if they should not be connected so there is clearance violation here.
There is a very good reason for doing the schematic first and then creating the PCB based off that even for simple circuits
ERC checks in the schematic will catch simple errors that you might have overlooked. It’s easy to forget to connect something. Going in blindly and just creating the PCB is asking for trouble. Yes, it can be done but not recommended.
DRC checks in the PCB editor will also help with fixing issues. Without a schematic the PCB is just in dumb mode and KiCad will not know what tracks should be connected. Easy to slip up and forget to connect something.
