Eagle- auto routing help

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Eagle- auto routing help

Post by blaze3927 » Tue Feb 08, 2011 2:26 am

G'day eagle users
so i started routing a board in Eagle, 2 layers, but after a few days I found manual routing too tedious and ended restarting with a lot of rip up's.
so after about 30 mins of auto routing i had the job done. and it looks very neat and tidy. However when turning the auto route into a pcb using the toner transfer method, i find the smallest traces it uses are too small and result in a few breaks in the copper after etching.

so to sum up.
how do I make the smallest autorouting trace in eagle large/thicker? and what would you recommend (in mm's please :p)as the lowest thickness i would go (realistically) to have the no breaks' when using the toner transfer method.

(i'll upload a pic soon of a quick pcb i etched comparing two different level thickness traces eagle used, one being too small with breaks, the other being perfect)
edit done:


Uploaded with ImageShack.us

thanks snow, ill give what you said a go in the morning. (except the manual route part :P maybe next time)
Last edited by blaze3927 on Tue Feb 08, 2011 4:16 am, edited 1 time in total.
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Re: Eagle- auto routing help

Post by Snow_Cat » Tue Feb 08, 2011 2:44 am

Well, I strongly reccomend that you minimize the use Eagle's auto-router as it tends to do extremely dumb things like weave traces around rows of pins when a strait path is unobstructed, stitch a trace through the active layers arbitrairly, make wiggly traces, and pepper your board with unnecessary vias.

As for tweaking it's behaviour, it follows the Design Rules that can be changed by typing the command 'DRC' without a ';' or
the icon (directly under auto route in the tool box/bar) while in board view.

You could increase everything not 0mil or mm to a minimum of 20mil if you are going to auto route, then turn it back afterwards when you start tweaking. If the autoroute fails to complete relax the design rules by returning the clearance (8mil), distance(8mil), supply(10mil) and masks(4mil) to their starting values.

Most settings are well documented, however Eagle does suffer from translation mishaps in other dialog boxes.

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Re: Eagle- auto routing help

Post by Haunted360 » Tue Feb 08, 2011 4:30 am

Ah Snow Cat, YOU LEGEND! Always having great advice :mrgreen:

http://www.electro-tech-online.com/gene ... sizes.html

If all fails, you may have to rip up and re-trace MANUALLY, or set up auto-route to a thicker trace I guess...

You could also just do this on the PCB (with angles, curves, text, pads, sharp traces etc to really test them)


and see what trace is the best / optimal outcome...

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Re: Eagle- auto routing help

Post by Snipeye » Tue Feb 08, 2011 4:29 pm

I find that the best way overall to do it is get your components how you want them, autoroute, then fix the mistakes autoroute made (stupid, stupid, ugly mistakes) and 're' route manually, optimizing everything. If you are rip-up-ing tracing, and you click on a trace, it rips it up. if you click on the yellow line, it removes all the routing, too - just click on the trace, not the routing, and you can see exactly where you need to go.

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