In the Drill Identification Drawing layer, the program automatically assigns a letter to each of the drill sizes to be exported. It seems to do this randomly. My question, should I be changing these letters to match some IPC drill size standard? I've never done this in 8 years of (occasional) board design work. I've always plotted them as whatever letters the program assigns and no issues. However, I'm wondering if it would be "more" correct to follow some sort of letter-to-drill size standard?
Well, based on these reactions I think I'll try my best to leave this alone although the temptation to hit buttons remains.
I had the idea that someone at the board house may use the letter identification based on some IPC standard and my drill sizes would come in wrong. As you folks stated it's never happened before.
Your Plot Report.txt file assigns the actual drill size to the Dril Ident letters anyway, so your pcb manufacturer should go by that. I therefore doubt that there's a "IPC" standard of assigning Drill sizes, -but I'm not expert in that field.
We use it as a check that the drill holes match a set list of approved drill sizes. This ensures you don't have some random number such as a 3.412mm hole.
In our case that would appear as a very large cross and therefore be corrected to a 3.4mm or 3.5mm drill depending on the requirement.
Drill Ident setup
Posted - 12 Feb 2020 : 17:49:47
