Trace Insulation

Dumb question, but I’ve spend way too much time looking through all the config menus…I’m using 5.0.3.
While tracing routes, there appears to be a keep away zone or insulation around the wire trace. It’s preventing me from getting to the small pitch IC pads. What menu allows me to change this zone thickness?

What you are looking for is the clearance around the traces which is set in the net classes. I don’t have (wait… 5.0.3? I didn’t think that version existed anywhere… do you mean 5.0.1_3?) 5.0.1 installed on this machine, only on my work machine (which I won’t be seeing again until Monday) so I don’t remember exactly the window to open. Look for net classes somewhere, and edit the net clearance there. You may also want to check the design rules minimum clearance.

Careful to not set these clearance and trace width values to less than your board house can make, or you may have an ugly surprise when you go to have your boards manufactured.

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It’s called “clearance” or “spacing”. In KiCAD you set it in the “Design Rules” editor, available on the topmost menu bar. You may set different values for different nets in your design, though many folks use one default value for all of the nets in a design.

In practice, the clearance is seldom limited by its insulation value but rather by manufacturing tolerances. Your design may show a spacing of, say, 10 mils between two traces but the finished board might be anywhere from 5 mils to 15 mils. This is due to accumulated errors in positioning, photo imaging, and etching. In modern manufacturing processes the clearance value applies to ANY two copper features - traces, pads, fill zones, etc - although in the past there were sometimes different requirements for various combinations (trace-to-trace, trace-to-pad, pad-to-fill zone, etc).

The board fabricator will tell you the minimum spacing he is capable of producing without copper features running together and creating an electrical short circuit between two nets. Currently, 6 mil spacing is considered a “routine” job by most fabricators; you may be able to get 4 mil spacing at extra cost; and some fabricators may require 8 mils.



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