Gerber of negative plotted layer

Suikan wrote:

Hi.

 

I am almost reaching the finish of my first 4 layer project with Eagle

4.14r2. But struggled. I am very much appreciate if somebody give me

comment.

 

I set the name of layer 2 and 15 as $GND and $VDD, respectively. So,

both are successfully connected with power. Both layers are showed as

negative image on Eagle PCB editor. This is as written in the manual.

 

After generated Gerber, I confirmed result with Viewmate. Both $GND

and $VDD layer is showed as negative. OK.

 

But I found all 4 layers Gerber has following declaration.

%IPPOS*%

%LPD*%

<<

That mean, all layer data is positive plotting. Strange. As I

described above, inner layer ( 2 and 15 ) is negative, and outer

layer ( 1 and 16 ) is positive.

 

Is this usual among the CAD vendor and PCB manufacturer? If yes, how

come manufacturer can know given file is positive or not?

 

Thank you in advance.

Regards,

Suikan

I can't comment on the apparent contradictions in the Gerber files.

However, I would avoid the entire issue by not using the power layers.

Instead, use the inner layers as standard layers, and simply draw GND and

VDD polygons on those layers.  That way you can view them in an easily

understood way in Eagle, and there will be nothing different about the way

these layers are plotted in the Gerber files.  Also, this approach allows

you to draw other traces on the inner layers, which is often very useful.

--

Bert Menkveld

Bert Menkveld <bert@betech.biz> wrote:

...

However, I would avoid the entire issue by not using the power layers.

Instead, use the inner layers as standard layers, and simply draw GND and

VDD polygons on those layers.  That way you can view them in an easily

understood way in Eagle, and there will be nothing different about the way

these layers are plotted in the Gerber files.  Also, this approach allows

you to draw other traces on the inner layers, which is often very useful.

I agree with Bert. With supply layers, it is also easily done that you

output the vias together with the ground plane. That way, the whole ground

plane gets isolated and useless.

Been there, done that

--

Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt

-

Tel. 06151 162516 -

Fax. 06151 164321 -

Bert, Uwe,

Thank you very much. It seems better to use the positive image by

polygon, rather than negative image by power plane.

I will modify my board.

Again,

Thank you.