I routinely have to route boards that use a chip with an MLF footprint. This is a pain when manual routing because the clearance has to be dropped from 12 thou (US "mils") to 6 thou when connecting or editing tracks attached to its pins. However, I don't want to do the whole board at 6 thou because it's unnecessarily risking inter-track shorts.
I would like to be able to use the Freerouter autorouter so I don't have to spend so much time routing. That means I need to somehow be able to tell Freerouter to use 6 thou for the MLF device and 12 thou everywhere else. It will AFAIK do this (if I define a clearance class "mlf"), but kicad seems to export tracks with just one track clearance, "default", which of course I want to have a clearance of 12 thou. I can't find find a way to manually define another track class and tell Freerouter to use it for the mlf pins. I'm currently experimenting with fanning out the pins on the mlf device, but of course the direction chosen inevitably isn't optimal and then the autorouter ends up stuck. I would appreciate any suggestions on how to solve this problem. If I manage to find a solution I'll post it. Regards, Robert.
