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Questions about the BatchPCB service

Moderator: robacarp

#4949
I would like to offer some ideas that may help to clear up some of the data problems you are having.

First I would like to say thanks for providing this service, I think you are brave to try and put this together, being a PCB design professional for the past 20+ years I have a good idea how difficult this is.

On your FAQ page where you state that you need RS274X Gerber data, I would further specify the precision (usually stated as 2.3, 3.5, etc) also specify what type of zero padding/suppression you expect, this can be leading zero suppression, trailing zero suppression, or no zero suppression. In some machine code languages (like for CNC mills) there is actually a decimal point in the data, why Gerber data did not do this ?? who knows. It may be worth noting that Gerber also allows for either absolute or incremental (delta) coordinates, but I have never seen a CAD system that used incremental coordinates, but you could specify that the data is in absolute coords.

Also I read that you felt that your CAM software required an XY pair of coords for each data point, rather than the modal style of only specifying the X or Y that has changed from the previous coord, is this the case? It would be rather unlike most Gerber or Excellon data I am familiar with. But if this is truly required it would be good to specify this on the FAQ page.

Similar requirements for the Excellon drill data, precision, zero suppression.

Also worth mentioning that the units are expected to be in inches.

The FAQ page could have links to text files to show examples of the expected format.

I am interested in this service for hobbyist work and not for professional work.

Thanks again ! ...John
By johnmcivor
#4969
Just found the actual FAQ page, I was looking at the order page. You have done a nice job of specifying the requirements.
User avatar
By sparky
#4974
Thanks!

Keep asking questions - we'll keep filling in the holes.
First I would like to say thanks for providing this service, I think you are brave to try and put this together, being a PCB design professional for the past 20+ years I have a good idea how difficult this is.
Thanks! And I probably should have talked to someone like you first. The service is running currently, but we're constantly fighting it.

-Nathan
By Steve
#5009
In some machine code languages (like for CNC mills) there is actually a decimal point in the data, why Gerber data did not do this ??
I seem to remember reading in the old 'Gerber Format Guide' (probably impossible to get hold of these days) that decimal data IS allowed (specified in the format statement) but it's not mentioned in the more recent PDF file. I'll check next time I look at that book.

Excellon does allow for decimal data, which overrides whatever digit format is current.

A bigger problem is that most software that *reads* these formats probably doesn't accept decimal format.

As an example, the tool sizes in the Excellon header can be written in the same format as the coordinate data, (ie: LZ, TZ) but nearly all software writes the tool sizes as decimal and the coordinates as LZ or TZ mode. Having decimal tool sizes is an example of overriding the current format.

CAM350 will *only* accept decimal tool sizes, but will NOT accept decimals in coordinate data. Go figure.

Everyone has a different idea on how to do things, it seems ;)

I've seen the occasional incremental mode file, but I think they were a result of the person exporting the file not knowing which to choose and guessing wrong. (well, not really 'wrong', but 'non industry standard'.)

Steve.