PCB Scaling problem
Originally Posted by
negativ3
...Am I chasing the wrong issue here, or would you suggest I look at something else?
Thanks a lot.
I have no experience milling my own PCBs. My last batch of small FR4 PCBs cost me all of AUD1.40 each, including registered airmail postage from China to Australia (for a batch of 10), and these are double-sided plated-through silk-screened both sides and HASL finish. I'm sure the materials alone would cost me more than that if I chose to mill my own, not to mention my time, and with a much less professional result.
Nevertheless I recognise that some people might want to mill their own boards for other reasons (delivery speed for one – those Chinese boards take 2 - 4 weeks to arrive after I e-mail my Gerbers!), so here are my thoughts...
The solution you propose should achieve the desired end-result, but I feel it's not the best approach. Gerber files from a good PCB CAD program are accurate to at least one thou (0.025mm), so something is going wrong between the Gerber output from Eagle (assuming it is a 'good' CAD program - I have no experience with it!) and the production of G-Code files for Mach3.
If it were me, I would be checking every step of that conversion process to determine which program is doing it wrongly, then I would junk that program and get a good one. Or at the very least e-mail the author to see if they can fix it.
This checking process might not be easy, at it probably requires that the file format for each output stage is known and understood. If this is not the case, see if you can beg/borrow/steal an alternative program for each stage, and by using those see if you can nail which of the original programs was the culprit.
Good luck!
Regards, Daniel
(Gerroa, Australia)