1.27MM Hole Spacing

Help DRC, here are global settings

r

Nick wrote:

When creating holes of 0.75MM in diameter spaced 1.27MM apart, I'm able to

size the pads the way I want to, without them touching each other (more that

0.005" of spacing, 0.127MM) . However, when I go to the device view with an

image of the package, it shows the pads are now touching each other, which

means all the pins are shorted together.

You've got to adjust the 'Restring' settings in the DRC options. Reduce

the Min and % values to avoid overlapping pads. Be careful not to exceed

the restrictions of your PCB-house.

Markus

Nick wrote:

Hi,

 

I'm trying to create a new device (with a new package) that is a simple 25

pin header. The pin spacing, however, is 1.27MM with a 0.75MM diameter pin.

 

When creating holes of 0.75MM in diameter spaced 1.27MM apart, I'm able to

size the pads the way I want to, without them touching each other (more that

0.005" of spacing, 0.127MM) . However, when I go to the device view with an

image of the package, it shows the pads are now touching each other, which

means all the pins are shorted together.

 

Is there something I'm missing, maybe a setting for a min diameter for a

pad?

 

Thanks for any help,

Nick.

 

 

It is the wonders of eagle's screwed up DRC

You design a package which is marginal with respect to annular ring, but you

are prepared to make an exception for this part,say. BUT eagle applies its

the global DRC setting - thinks it knows better than you and makes all the

pads bigger as the one you set explicitly violates its own idea of what your

annular ring (restring) parameters should be.

Strangely enough this then violates the min pad to pad clearance, but that

would apparently be applied after the restring parameter - Its a genuine

check rather than the resting parameter which is a ch

Once more eagle should NEVER change anything the designer does without first

asking if this is acceptable.

The solution is to reduce your global restring parameters- NOTE that this

parameters is not something that is simply checked but a global design rule

change.    In you case you will need to reduce the min restring for pads

to less than 0.1mm - this is not good for production but you could also use

elongated pads to improve things.

I really like Eagle, but I absolutely loathe this aspect of the DRC.  Please

get this sorted- check my design DO NOT CHANGE IT without asking me.

cheers

David

On 07/14/08 11:03, David Moodie wrote:

...

It is the wonders of eagle's screwed up DRC

 

...

Once more eagle should NEVER change anything the designer does without

first asking if this is acceptable.

 

...

Please get this sorted- check my design DO NOT CHANGE IT without asking me.

The minimum restring requirement is something the board manufacturer

will tell you. If, at any place, your board violates this requirement,

this will typically cause the board manufacturer to get back to you

and tell you that this board can't be manufactured at all, or needs

to use a different manufacturing process, where the increased level

of precision can be achieved.

If you don't want EAGLE to assure the minimum restring requirement

automatically, you can set this parameter to 0 in the design rules.

It will then use exactly the diameters you have set in your libraries.

Klaus Schmidinger

--

_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10

CadSoft Computer GmbH                   Fax:   +49-8635-6989-40

Hofmark 2                               Email:   kls@cadsoft.de

D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de

_______________________________________________________________

Klaus Schmidinger wrote:

The minimum restring requirement is something the board manufacturer

will tell you. If, at any place, your board violates this requirement,

this will typically cause the board manufacturer to get back to you

and tell you that this board can't be manufactured at all, or needs

that's not true in any case.

I can use some vias with smaller "restring" (or no "restring" at

all) without any problem, and I want to be able to do so.

But I want to be warned about this, and currently Eagle has no

design rule check for minimum "restring". That's a severe drawback

since version 4.

After all, check and change must be separated nevertheless.

Greetings,

Oliver

Klaus Schmidinger wrote:

On 07/14/08 11:03, David Moodie wrote:

...

It is the wonders of eagle's screwed up DRC

 

...

Once more eagle should NEVER change anything the designer does without

first asking if this is acceptable.

 

...

Please get this sorted- check my design DO NOT CHANGE IT without

asking me.

 

The minimum restring requirement is something the board manufacturer

will tell you. If, at any place, your board violates this requirement,

this will typically cause the board manufacturer to get back to you

and tell you that this board can't be manufactured at all, or needs

to use a different manufacturing process, where the increased level

of precision can be achieved.

Yes... the board house runs a real design rule check

Then they warn you of any failures

Then after you explicitly approve the design they will go ahead.

You still want to know how many and what marginal issues exist but you do

not want them changed without approval.  So check is good change (without

approval) is bad.

cheers

David