Eagle, ExpressPCB, Gerber...a little confused.

[Nocaster Cat]

ExpressPCB is starting to become a hassle to use (the company, not the software). I've been submitting boards to them for years and I can submit a board design that gets manufactured without hassle and then submit the same board design again with no changes and it will be rejected for design violations. When I ask them why this happens I get vague answers, so I've been thinking about requesting the Gerber files from them so that I can have my boards fabbed anywhere. My question is this...once the Gerber files are in my possession, how would I go about making changes to them, ie. what software would I use? I've messed around with Eagle and it seems the end result in a .brd file and the Gerber files are generated in the background (?). I see that fab houses like 4 PCB and PCB Express offer their own free design software but I don't want to get stuck in the same position I'm in now (not being able to take my files where I please). I've tried the methods mentioned online to convert ExpressPCB files to Gerber but they seem less than reliable and generate quite a few errors in the DFM checks I've run. I know the quick answer would be to just get the hang of Eagle but if I could ease the learning curve by working with known good files that would help. Any input would be greatly appreciated.

[MoltenVoltage]

bite the bullet and set aside a few weeks to get eagle down

[mattthegamer463]

Gerbers are a pain because they're basically raw numerical data that represents the board layers.  There's no objects or any association between any of the lines or anything, just gridpoints joined by lines.  They can be edited but it is tough and delicate.  Errors slip through the cracks easily.

You are definitely better off finding a CAD package you like the look of and getting the hang of it.  They all have very similar features, it's just a case of finding out what all the buttons do.  PCB technique is something learned regardless of software suites.  I prefer a package called Proteus, it offers schematic drawing, simulation, and PCB layout.  I get my PCBs from Seeed Studio.

[R.G.]

ExpressPCB is starting to become a hassle to use (the company, not the software). I've been submitting boards to them for years and I can submit a board design that gets manufactured without hassle and then submit the same board design again with no changes and it will be rejected for design violations. When I ask them why this happens I get vague answers,

Express PCB does things the way they do for a reason. They give you free software to use *because* they make their money on a captive audience, buying PCBs from them. Otherwise, they would not give you free software. They are going to be difficult to get Gerber from, because every request for Gerber means the customer is taking their business elsewhere.

As to why you get process violations one time, but not another, it's likely that their process rules and/or checking software changes over time. As Napoleon said, never ascribe to malice what can be explained by incompetence. Shrug. Fix the design violations. Takes a few minutes. No biggie.

Or, as you've said, if that's too much trouble, go elsewhere.

so I've been thinking about requesting the Gerber files from them so that I can have my boards fabbed anywhere.

This may not be simple and easy to do, for the reasons I mentioned.

My question is this...once the Gerber files are in my possession, how would I go about making changes to them, ie. what software would I use?

Basically, you don't, for the reasons Matt mentioned. Gerber is best thought of as an output-only medium. In fact, that's how it started. Gerber files consist of directions to move a light source in an X-Y direction and to turn the light on and off, or change the size of the spot ("aperture") on a plotter which uses photographic film for paper and a light source instead of ink.That is literally how it was done before personal computers made it cheap to deal only with the output as pure numbers. Gerber files are corrected the same way as printed paper is - hacking out the printed area some way and overwriting it with hand-applied print. They are editable, but that's not what you want to do. Software and learning to use it to edit Gerber is as complicated as learning to use a proper PCB program in the first place. Don't edit Gerber, for the same reasons don't run with scissors - you'll hurt yourself.

I've messed around with Eagle and it seems the end result in a .brd file and the Gerber files are generated in the background (?).

All pcb software does that. They use a format that's easy to edit, like Gerber is not, and then generate Gerber as an output.

I see that fab houses like 4 PCB and PCB Express offer their own free design software but I don't want to get stuck in the same position I'm in now (not being able to take my files where I please).

Then look at every package which you consider, and find out if it explicitly says it produces Gerber as an output. If it doesn't, look else where. What's hanging you up is the word "free". The free packages do things that used to cost a few thousand dollars a license. The companies that make PCB packages for a living still do. So look at the free packages, see if they output Gerber, and move on if they don't. When you find one that does, go learn to use it. There is a price to everything. Learning to use a free package is the price you pay for your freedom, both metaphorically and literally. Freedom is not free.

I know the quick answer would be to just get the hang of Eagle but if I could ease the learning curve by working with known good files that would help. Any input would be greatly appreciated.

You might google "free PCB design software". There is at least one package that's released as open source that produces Gerber. But again, you're looking at learning the package to pay for getting it free.

The internet has produced the popular idea that everything should be free. Sometimes it's not.

[.Mike]

ExpressPCB -> PDFCreator -> Pdf2gerb.

Never used it, but it looks like it could work. Otherwise, I think you can get Gerbers from ExpressPCB for $60.

Mike

[Nocaster Cat]

RG...heard, understand and thanks. Also, ExPCB will sell you your Gerber files for $75 after you've used them at least once for the layout.

What's extremely frustrating is that three weeks ago I submitted a design to ExPCB and it cleared without issue. A week later, I submitted the same design and it failed. A few days later I submitted it again and it cleared. From what I was told by someone "in the know" is that ExPCB uses multiple fab houses, so what clears one manufacturer's rules may not clear another's rules, it all depends on whose turn it is in the rotation. The same person was also kind enough to thoroughly (and in layman's terms) explain Gerber files to me and between his explanation and everyone here I now get it.

ExpressPCB -> PDFCreator -> Pdf2gerb.

Never used it, but it looks like it could work. Otherwise, I think you can get Gerbers from ExpressPCB for $60.

Mike

Thanks Mike, I'll give it a try and report back.

[The Tone God]

I see someone fell into the trap that I keep warning people about when it comes to using vendor tied software. To recap yes these software packages are easier but you are stuck with one board manufacture. Learning real PCB software while tougher in the end you have your freedom.

There is actually a trap with the free version of Eagle besides the size restriction and that is it is only free for personal use. Once you sell anything you are now commercial and need to buy a licence. I know some people choose to ignore this little fact but I prefer to do things properly.

For what its worth I use Kicad and am quite happy. I did use gEDA for awhile but Kicad is put together better. Free, open source, and no limitations. Still has the typical difficult CAD interface but I don't think there is anything that we do in our field that Kicad can't do and Eagle can. Maybe libraries but you can make your own anyways. I think there was a conversion tool for Eagle to Kicad libraries too.

Andrew

[R.G.]

ExPCB will sell you your Gerber files for $75 after you've used them at least once for the layout.

I didn't know that. Probably reflects me willfully not wanting to know. I do use ExpressPCB, but I do my layout in another PCB suite, and then manually re-lay the thing in ExpressPCB for their cheapest deal. In my case, I know ahead of time that I will accept their "captive" offer, but I accept it in a way that works for me. Re-laying in their stuff isn't as hard as it sounds, because the package I use lets me redefine the coordinates into their screwy positive-Y-is-down format, which is a more subtle impediment they put in there. This also lets me get around my real objection to ExpressPCB - it's complete lack of a useful (!) connection to a schematic, and total lack of an online error detection routine for following whether you have accidentally connected the wrong nets together. Doing it first in the useful PCB suite lets me do the layout fast and error free, and then the coordinate thing lets me put part in places I already know will work, and then run the traces.

It works for my limited needs, anyway.

What's extremely frustrating is that three weeks ago I submitted a design to ExPCB and it cleared without issue. A week later, I submitted the same design and it failed. A few days later I submitted it again and it cleared. From what I was told by someone "in the know" is that ExPCB uses multiple fab houses, so what clears one manufacturer's rules may not clear another's rules, it all depends on whose turn it is in the rotation. The same person was also kind enough to thoroughly (and in layman's terms) explain Gerber files to me and between his explanation and everyone here I now get it.

The multiple fab houses makes sense.

I've never had Express PCB flag a design rules problem, but then I design very conservatively. I tend to use the same sizes of holes, pads and other stuff. I never come close to the claimed hole sizes and trace/space rules they have. I also do not use SSOPs, leadless/etc. ICs, nor 0204 SMDs. For instance, my smallest hole is usually 0.028, largest about 0.157 (for mounting screws), and traces are at a minimum 0.012.

I take that back. They did tell me that I had a part too close to the edge once.