Eagle-polygons-rectangles [1 Attachment]
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What you describe is an issue, the little slivers, yes. Increasing isolation really isn't always a solution since it usually just changes where they occur. What I do is just ignore them and address it after the board is milled by wire brushing then snipping them out with an exacto knife. I also snip off the little acute angled "tips" of copper that sometimes occur and tend to raise up a bit. Finally I sometimes soak the board in etchant for a couple minutes and then in an ultrasonic cleaner before soldering begins.
I haven't tried it but you might try drawing your rectangles on what the ULP calls the "milling layer" instead of the actual copper layers. This layer is used for adding text and routing the board outline. On that layer I don't think you have to name them since they are just lines. Just remember the tool will follow the lines as its centerline. I suppose you'de have to draw the rectangles two times, once for milling top, then bottom sides. But should be easy.
From: Roy Emeny
Sent: Friday, January 31, 2014 7:02 AM
Subject: [pcb-gcode] Eagle-polygons-rectangles [1 Attachment]
[Attachment(s) from Roy Emeny included below]
Sorry if there is an answer elsewhere - found lots of references but nothing helpful.
Having a great time making PCBs thanks to Eagle and pcb-gcode.
Problem using Eagle conventionally is it produces nice looking boards but often tiny areas of copper are left between tracks and around components. These can give rise splinters and shorts.
My mill isn't the most accurate - so simple functional, non-artistic boards are fine by me. The best method I have found so far is create ground planes on both sides using polygons with thermals off - (thanks for previous help in this respect). Then routing the board with thin tracks so I can see how everything connects on both sides. Then filling the board with rectangles over these thin tracks on either top or bottom layer - rectangles are so quick with only two defined points (using alt and finest grid setting).
Milled results are good and tend to contain only half as many gcode instructions, thus quicker. By ensuring that the gap between adjacent rectangles is only say 0.2 mm the mill effectively goes in almost the same path twice clearing any splinters.
But there is an issue, because you can't name a rectangle as you can a polygon, Eagle doesn't recognise them as part of your nets so they can't be speedily ripped up. There is also a danger of nudging them out of place when moving component names etc when tidying up an eagle file to pass on to others. I wonder what others are doing? Is there a way of naming rectangles or creating a polygons as quickly? - I find the latter very fiddly and slow to use for creating in large quantities. Have attached a jpg - as you will see the quality of my soldering doesn't warrant an artistic board - really must get a new poker ....