I have a DB9 serial port type connector on the board I just designed. My question is this.
The outline of the “snout” of the connector goes outside the outline of the circuit board, as I do want it to hang over the side of the board. This outline was carried over to the silkscreen layer when I ran the “silkgen” job. Is this going to affect the size of the board? will the board be routed to the outermost tip of the silkscreen? Again, my intentions were for the plug part of the DB9 to hang over the side of the board.
To avoid any possible confusion, I usually go into the silkscreen layer and delete the any portion which hangs off. The silkgen I use puts the output on layer 121/122 so its easy to open up the layers and delete any extra bits I don’t want (without losing any real data from my design).
For connectors that overhang, I move the overhanging parts of the outline to the tDocu layer in Eagle. This causes them to show up the same during layout, but the silkscreen doesn’t print beyond the edge of the board.
With it overhanging in the silkscreen layer, you’d probably end up with an odd-shaped board with a stub sticking out under the jack because SparkFun uses all layers to identify the board outline shape. It’d also extend your board dimensions, which could affect the price a little.
Hmm, I would have thought that the gerber files would have been hacked off at the board outline. I guess not. I’m glad I haven’t submitted my next board yet. Thanks parts-man73 for asking that… it’ll save me a bit of board space and some hacking time.
For connectors that overhang, I move the overhanging parts of the outline to the tDocu layer in Eagle. This causes them to show up the same during layout, but the silkscreen doesn’t print beyond the edge of the board.
It took me a few minutes to understand this suggestion. You need to edit the outline in the parts library package and set the area which overhangs the board to _tDocu (the rest stays in _tPlace). Silkgen skips _tDocu and thus does not produce silkscreen outside the board dimension for that part. Cool solution to the problem since you only need to edit the part once.
Vraz - exactly what I was trying to say. Thanks for translating.
Kuroi - it all depends on what’s used to determine the board outline. Some board houses use a specific Dimensions layer to define the board outline (and interior routing). Most board houses will also only make the PCB rectangular based on the largest dimensions.
SF’s process is less complex for the user - they figure out the board outline (and pricing dimensions) automatically using the outline of all the layers combined. SF will also cut the shape of the outline, so you can make the PCB a unique shape.
Actually, I did double check the dimensions of the current rev of the board (still sitting in shopping cart), and they’re off by exactly how much the connectors overhang the edge of the board. So regardless of whether they’ll trim it correctly, I’d still be charged the the overhang dimensions.
Yeah, Kuroi. While SF will cut the shape to the outline of the layers, they will still charge you for the rectangular area that envelopes it. E.g., a “T” shaped PCB that’s 2" wide and 2" tall would bill as 4 square inches, not just the area inside the finished PCB.
Thanks for translating.