Board Characteristics | Pulling from Design Rules Instead Of Design

Manufacturing
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Hi everyone,

I just ran into a somewhat embarrassing situation. I’ve sent files out for quote with a few different board houses, and the first response I get back is calling out a discrepancy between my fabrication drawing and the design files.

“… in the notes section that the fab notes say the min hole is 8 mil but I found the smallest hold is 20 mil in the gerber.” I didn’t double-check the board characteristics auto-generated information closely enought before exporting my files. Sure enough, 0.2032mm is not 0.5mm. My drill file confirms that 0.5mm is the smallest hole used in my design.

After digging around my project and verifying that I do not in fact have any 8mil holes, I finally found the magic “0.2032mm” value. In my design rules.

In my mind, the design rules should serve as the absolute bounds for a project. My fabricators have specific capabilities, and I want to ensure that I do not exceed them. Whether my design uses those minimum (or maximum) values is irrelevant in my mind. I use them more as global design rules, applicable project to project.

Is there a way to have the Place → Add Board Characteristics feature pull from the actual design and not the design rules? I suppose a script could possibly be used to parse the smallest drill data from my .drl file and then import that into the table, but that seems a bit excessive.

Thanks, and please let me know if I’ve overlooked a way for this to be done. Not ruling out user error. It wouldn’t be the first time :smiley:

2

Why not simply turn it around and keep it simple. Set PCB Editor / File / Board Setup / Design Rules / Constraints to the minimum values you actually want to use (I.e, your 0.5mm hole)

3

If you pull up the Board Statistics from the Inspect menu, it can tell you a lot about your board, including all of the drill sizes. This is one way to verify all of the drills and vias are within the required specs. This is extremely useful for checking Blind via stackups, when you have thousands of vias.

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1 Like
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I would prefer to have my design rules set to follow manufacturing constraints and then allow myself the freedom to design as I see fit. If I set a design rule to follow 5mil trace/space constraints for price/fab reasons, I want that rule to help enforce the minimum values I can implement. However, if I have sufficient board space available I may want to increase space between traces. I don’t want to have to go back to my rules just to have accurate board characteristics.

Maybe it’s a bit of a misnomer to have this feature implemented as “board characteristics” if it is really design rule characteristics + some board characteristics.

5

Yes, that is a quicker method to check board information than generating a drill file and inspecting the file. Is there a way to have the board characteristics information pull from this table rather than the design rules?

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