Hi,
My position file from kicad has a few distinct errors in it. Some large components are rotated. I have no idea how this happenend, i can manually change it in the posfile but that is asking for trouble. Does anyone have an idea what it can be? Is there something that you can do with footprint design?
I’ve already messed up an order this way and i dont know what causes it
Well did you create the footprint in the zero orientation that is expected by the fab? Note that the official library typically uses zero orientation A (pin 1 at top left corner).
I have never thought this about this when creating footprints. Do you have a link to where i can find more info on that? I cannot find it in the normal channels.
Thanks alot Rene!
The first step is to ask your fab about their guidelines. I am quite certain that they will provide you with information on how they determine the zero orientation.
There is a helpful blog post about component zero orientation here https://blogs.mentor.com/tom-hausherr/blog/tag/ipc-standards/
and you can download a Mentor document from here
http://s3.mentor.com/public_documents/technote/resources/appnotes/zero-orientation-cad-libaray.pdf
Just to show how confusing it is, here are three competing standards - hence why you need to check carefully with your supplier.
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The column for IPC-7x51 is listing only one of the two options (It lists zero orientation A. There is also zero orientation B)
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This discussion also emerged here JLCPCB BOM and Pick and Place
Maybe the the “Generate Footprint Position Files” windows could have a option about the two standards. There are just these two? (Last board that I used a manufacture house, I “manually” rotate the transistors scraping the position file).
Another JLC workflow you can try: https://dubiouscreations.com/2019/10/21/using-kicad-with-jlcpcb-assembly-service/
Okay, i am still pretty confused. Is it specific per footprint what the orientation is? Isn’t there some sort of anchor that you place that determines what the zero point is? it feels really really odd that with the tech nowadays we have this problem…
yes, i always place pin 1 at the top left corner
I “manually” rotate the transistors
Unfortunately IPC only defines the 0 degree but does not define direction CW or CCW where Mentor is diffrent from Eagle. (that is 0 and 180 degree correct but 90 and 270 degree swapped) Another pitfall waits for Altium users what mirror CW/CCW if component pushed to solder layer while others do not …
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