I am using Eagle. I believe that it has a default set of drills. Are these OK for the Batch PCB designs, or should I use some other sizes. Specifically, I am wondering about the drill size for vias. I see from the SFE files, that they use a minimum of 20 mil drill for vias, but I bet that 20 mil is not a standard drill. What drill should I specify for vias. WHat happens if a PTH part in the Eagle library uses a drill measured in inches (e.g. .062") would that get rounded to the nearest (next larger?) standard drill in the drill set?
-Tony
can’t really answer your question, but I’ve used all different sized drills that are standard choices in eagle, and never had an issue. Also, why don’t you go check goldpheonix’s website, since they’re the supplier.
I thought this was a great question, but I didn’t find anything at the Gold Phoenix site other than min and max drill sizes. Wondering if anyone else might have found something I missed.
They will round them off to the nearest metric size, anyway. I wouldn’t bother about it.
leon_heller:
They will round them off to the nearest metric size, anyway. I wouldn’t bother about it.
Well, I do need to worry about it a little. I like to make my holes just the right size, not a little “too large” just to be sure. If I know what the PCB manufacturer is going to do, like round DOWN to the nearest metric size, I’d really like to know what that size is going to be!
Since I originally posted this message, I had a PCB made and it turned out fine. There were some holes that I would have liked to actually be smaller. One in particular, I used the SFE footprint for a small diameter electrolytic cap, and the holes were rather generous. I have to go back and check that package and see what drill they specified. It was bigger than even the leads for big caps! It worked, though!
-Tony
It’s best to use metric drills in the first place. You should then know exactly what size the holes are going to be.
It’s also a good idea to use your own parts.
leon_heller:
It’s best to use metric drills in the first place. You should then know exactly what size the holes are going to be.
It’s also a good idea to use your own parts.
Ah, but what exactly are the standard metric drills? 90% of the parts I use are of my own design, or at least I have double checked the pads/holes for position and size. I guess I did not check that one enough…
-Tony
They go in increments of 0.1 mm, but it’s best to check with SFE. This is what Olimex says about rounding etc.:
http://www.olimex.com/pcb/pcb-techinfo.html
An official list would be greatly appreciated.
leon_heller:
They go in increments of 0.1 mm, but it’s best to check with SFE. This is what Olimex says about rounding etc.:
http://www.olimex.com/pcb/pcb-techinfo.html
Olimex is unusual in the PCB manufacturing world, in that they use the actual drill sizes specified in the files (rounded to the nearest 0.1mm). All other companies I've seen (including Gold Phoenix) use slightly larger drills, so that the holes *after plating* match what is specified.
That caught me out once, I couldn’t get a header in a board they had made.