Gerber files errors and confusion


#1

Hi,
I have used Fritzing for some time and always etched my own circuits with constant success. However, I now want to use professional outfits but I am having problems.
I uploaded zipped Gerber files to one Chinese co. and they were excellent productions except they were mirrored so my ic footprint did not correspond.
I used Gerberlook and the results for a single layer board were ‘no top copper fill’ and ‘no top solder mask’. When I look at the actual files they are all bottom files. I have spent ages trying to work out this problem and have nothing to show for it.
Can someone please help me?


#2

Upload the sketch (.fzz file, 7th icon from the left on the reply bar) and I will have a look.

Peter


#3

EDA’s produce all the gerbers, so you need to take out the ones you don’t want and zip the rest.

Free stuff on the net is always a risk, so they have to be checked thoroughly.


#4

SZA 1 layer.fzz (40.6 KB)

Many thanks


#5

The gerbers look fine, but I see a few things. You have a top layer silkscreen (which likely isn’t what you want on a single sided board), although that isn’t likely your problem. What I think may be your problem is the parts are showing as bottom layer. On a two sided board that means the smd part is flipped so it would be correctly aligned if installed on the bottom of the board (rather than the top of a two sided board as is standard). A check of Q4 (comparing it to one installed on a two sided board in another window) indicates that is what the alignment here is. That would explain why the parts appear to be mirrored, they are supposed to be that way on a two sided board. If you routed based on the other way your routing will be backwards. Are you trying to install the parts as if they were on the top of the board (as would be the case with a two sided board?) If you install them as if they were on the bottom of a two sided board are they then correctly aligned? I’m not much of an expert in the pcb area, and I haven’t heard of anyone trying a single sided SMD pcb (although that doesn’t mean much), but that’s all that I see here that might explain this. However this circuit appears unlikely to work. Q4 for instance has no connection to the base. With nothing to drive it it won’t do anything. Q1 has no connection to the collector, while you may be using the base emitter junction as a diode, that seems unlikely. The 4081 both is not a fritzing part (there is one in current core parts) nor correct, it doesn’t have a ground and thus won’t work. I’d advise routing the schematic view of the board and make sure it is correct. That should put rats nest lines to the appropriate connections in pcb view. You need to delete all the traces in pcb view before doing this in schematic though, as conflicts can corrupt the sketch. The easy way to do that is in pcb view select routing->all traces and then hit delete. Hope this helps.

Peter