Tiny air wire scraps

On Sun, 15 Jun 2008 10:46:06 -0400, Larry Coyle wrote:

I seem to be plagued with numerous tiny air wires on a board I'm trying

to finish. These have the appearance of being "embedded" in the pads of

SMD components. Ripping up and re-routing doesn't get rid of them.

 

(But all of the copper trace connections seem to be OK.)

 

I'm guessing that the library SMD parts I'm using for some reason are

not on the grid (??!!), but I don't know any easy way to fix this. I've

tried using both metric and English measure -- didn't help.

 

SO, I have two questions:

 

1) If I just ignore these unrouted bits of air wires, and go ahead and

send the board out for manufacture, might this come back to bite me

later on?

 

2) Any way to avoid this, other than making my own library version of

every component?

 

 

And thanks in advance for the generous help on this news group.

 

 

-lmc

If this is the problem I am thinking of, I believe I have had it too.

Try this,

show only the unrouted layer, and highlight all the airwires and delete

them.  It won't delete the actual routes, (given your board and schematic

are consistent) but it will delete all the 'fake' unroutes, and then give

you and error "Can't backannotate this operation"

That 'should' get rid of those unneeded airwires.

But if that doesn't work, you can basically just try to re route the wire

(without deleting it) with a wire of a thinner size than the one you use,

just to make EAGLE work.

Hope this helps

Shawn

On 2008/Jun/15 11:53 AM, in article g33dt7$nl6$1@cheetah.cadsoft.de, "Shawn

Groce" <sgroce@rhinoequipment.com> wrote:

On Sun, 15 Jun 2008 10:46:06 -0400, Larry Coyle wrote:

 

I seem to be plagued with numerous tiny air wires on a board I'm trying

to finish. These have the appearance of being "embedded" in the pads of

SMD components. Ripping up and re-routing doesn't get rid of them.

 

(But all of the copper trace connections seem to be OK.)

 

I'm guessing that the library SMD parts I'm using for some reason are

not on the grid (??!!), but I don't know any easy way to fix this. I've

tried using both metric and English measure -- didn't help.

 

SO, I have two questions:

 

1) If I just ignore these unrouted bits of air wires, and go ahead and

send the board out for manufacture, might this come back to bite me

later on?

 

2) Any way to avoid this, other than making my own library version of

every component?

 

 

And thanks in advance for the generous help on this news group.

 

 

-lmc

 

If this is the problem I am thinking of, I believe I have had it too.

Try this,

show only the unrouted layer, and highlight all the airwires and delete

them.  It won't delete the actual routes, (given your board and schematic

are consistent) but it will delete all the 'fake' unroutes, and then give

you and error "Can't backannotate this operation"

That 'should' get rid of those unneeded airwires.

 

But if that doesn't work, you can basically just try to re route the wire

(without deleting it) with a wire of a thinner size than the one you use,

just to make EAGLE work.

This is a very bad idea.  You are deleting the "signals" that tell the board

editor what gets connected to what.  I believe you lose your consistency

when you do this (that is what the warning is telling you).

The problem is that your trace doesn't end up at the exact coordinate of

the center of the pad/smd.  So the delta is shown as an airwire.  The best

way to get rid of this is to route from the pad outward.  The end of this

route will be on your grid and thus be available as an exact match and thus

no airwires.

Cheers,

James.

--

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~                                          ~

~  James Morrison  ~~~  Stratford Digital  ~

~                                          ~

~  email:  sales@eagletoolkit.com          ~

~  fax:    888.701.8097                    ~

~  web:    http://www.eagletoolkit.com     ~

~                                          ~

~  Online EAGLE Dealer for US and Canada   ~

~  EAGLE Design Experts                    ~

~  EAGLE Enterprise Toolkit                ~

~                                          ~

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In article <g339ve$f45$1@cheetah.cadsoft.de>,

"Larry Coyle" <lmcoyle1@verizon.net> wrote:

I seem to be plagued with numerous tiny air wires

on a board I'm trying to finish. These have the

appearance of being "embedded" in the pads of

SMD components. Ripping up and re-routing doesn't

get rid of them.

After ripping the trace up, start routing at the offgrid pad and route

to an ongrid position.

This way, the new traces will be centered relative to the pads and you

get rid of these short airwires.

I'm guessing that the library SMD parts I'm using

for some reason are not on the grid

2) Any way to avoid this, other than making my own

library version of every component?

Making new packages in an own library won't help. There are many

packages with metric pin spacing (even through-hole components, e.g. the

2mm Metral connectors), and these will always be offgrid when you use a

grid based on inches.

So use the correct routing technique and you won't have problems.

Best regards,

Günther