Ahhh a question worthy of books of advice.  I'm sure others will pitch=20
in, here's my 2c.

If you haven't already, change the design rules to allow 16mil drill=20
vias, rather than the default.  DRC -> Sizes Tab -> minimum Drill set to=20
16, and I think the Restring Tab -> vias -> I have the min set to 8mil=20
outer and inner, % to 25, and Max to 20mil.

Humm.  Place all parts before doing any routing at all.  Decoupling caps=20
especially.

If you can do 8/8 and 16mil drills, this means you can use nearly any=20
boardhouse's typical cheap manufacturing.

Ground pour on top and bottom.  I don't do the +3.3V (or whatever) power=20
pour ever, even on 4-layer.  I always route power so I know what is=20
going where.  Ground I don't route, but am mindful of trying to keep the=20
pour successful.  Use lots of vias to ground, they're cheap and make=20
things easier.

I have a separate USB keypad with programmable keys (designed for=20
gaming) configured to switch between 9 different tools in eagle when=20
doing layout, so move/ripup/ratsnest/route is real fast to switch=20
between.  Left hand on keypad, right hand on mouse, with mousewheel of=20
course and click of mousewheel ("middle" mouse button) and drag is pan.=20
  Very very handy.  Essential.

You can use the autorouter to "check your work" ... if it is having big=20
problems with routing, you probably will too.  Move parts, watch=20
airwires, try to avoid long airwires that cross others, etc. etc.

For placing parts, I usually use a grid of 10mil.  For routing, 5mil.

It is pretty Zen.  I hand route everything, the autorouter is just for=20
getting an idea of difficulty, tho I'm still on eagle 4.x and I hear it=20
has been improved.  4-layer 2000 net pcbs, yes, by hand.  It does take=20
awhile, but with good parts placement, it almost "routes itself", mostly.

Have fun!
J







Bob Blick wrote:
> forwarding with tag added
>
> On Wed, Feb 8, 2012, at 03:59 PM, Marc Nicholas wrote:
>> Hi all,
>>
>> Does anyone have any "tricks of the trade" for hand routing boards?
>> Specifically, hand routing from reasonably high density TQFP/QFN parts
>> (44
>> and 64-pin) in 6 to 8-mil to other lower density components (think hub
>> and
>> spoke).
>>
>> I'm getting beyond the stage where Eagle's autorouter does a good job...
>>
>> Appreciated in advance.
>>
>> -m
>
--=20
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