Gibbions Files? PCB Design

You mean Gerber and/or Excellon?

I imagine he asked you for the Gerber files.

Since you're unfamilar with them, I'll advise you right now that supplying Gerber files is full of potential pitfalls. I still don't understand them fully myself, but be aware in particular of the 'aperture file'. You'll be better off finding a supplier who can read your cad's native file format to be honest.

Graham

Thanks! It was Gerber he said! I'll see if they can take what Eagle puts out.

There should be a Gerber file for each layer, an aperature file, and a drill file. Eagle should make them all.

John

However, my understanding is that making sure they are 100% correct is not a trivial task.

At the very least you should preview your gerber files.

Graham

I've only heard of Gerber files, not Gibbons.

Agreed

I have not used Eagle for the entire design process, so I am not aware of the options available, but in the packages I _have_ used, there are numerous (and to the untrained eye confusing) options for gerber (RS174X, incidentally) outputs. Some manual tweaking of the output options is often required. Having said that, every layout package I've used had an output option to generate gerbers using the layout settings (for such things as inverse layers etc).

The OP could try the automatic generation from Eagle and then look with the gerber viewer from Graphicode.

Cheers

PeteS

IIRC, the output of our CAD layout system was reviewed by two engineers for three-to-five days before we sent them to the PCB manufacturer. I don't know what's so tricky about the Gerber files, but there seems to be something tricky about them.

Indeed, for the best results, the reviewers should not be disturbed at all for that five day period (no boring^H^H^H^H^H^H distracting department meetings, for example) and should be amply supplied with their chosen energy boosters, such as fresh doughnuts, hot coffee, the occasional pizza, and so on. Optimally, they should have exclusive use of the "big conference room" - the one with the really giant display - for that period as well, the better to view the projected Gerbers.

Any outbursts that might be overheard like "Damn! Nice shot!" should be interpreted to mean that somebody pointed out where a mis-placed via punched into a ground plane.

We never look at our Gerber files... we just email them to the board house. Occasionally the board shop will come back with a question... apparently they have their own, probably automated, checks. Dead-end guard traces especially freak them out. They also don't approve of inner planes that go all the way to the board edge, and sometimes ask our permission to pull them back a tad.

It's very rare that we have any board problems that weren't obvious on the schematic.

John

Le Sun, 02 Sep 2007 19:35:31 -0700, John Larkin a écrit:

Yup. I really wonder too. Never had or heard of the tiniest problem about gerber files in 20 years.

I've been (indirectly) caught out by it for sure in 1999.

It was an aperture file problem IIRC. Maybe it was Cadstar's fault that it didn't translate properly but the board certainly didn't match the layout. Note this the problem related to an elongated pad.

You have to know that Gerber's a bit like HPGL in that it calls 'primitive' draw functions and that gives plenty of scope for f*ck-ups.

Be careful about your drill file too.

Graham

Le Mon, 03 Sep 2007 09:01:48 +0100, Eeyore a écrit:

I've for long, as I guess almost everybody, switched to the extended gerber format which carries the apertures within the drawing files. No mix up possible there. CAD packages can still possibly do errors, but it's a software related problem. Don't blame the file format for this. And I don't see how this (SW bug) can last long or the vendor has just to die.

Le Mon, 03 Sep 2007 09:01:48 +0100, Eeyore a écrit:

I've for long, as I guess almost everybody, switched to the extended gerber format which carries the apertures within the drawing files. No mix up possible there. CAD packages can still possibly do errors, but it's a software related problem. Don't blame the file format for this. And I don't see how this (SW bug) can last long or the vendor has just to die.

That there is this 'extended Gerber format' that embeds the aperture file has to be good news.

This wasn't the case when I had my big problem with Gerbers.

How does one know which standard one's CAD package outputs Gerber data in ?

Graham

Le Mon, 03 Sep 2007 10:06:41 +0100, Eeyore a écrit:

Select the format when setting/generating your gerber output. RS-274D for the standard separated gerber/apertures files RS-274X for the extended format.

Obviously if you look at your files, you should find an aperture definition section in the 274X file.

Oh thank you for your words of wisdom my God.

I bow to your prescience.

Graham