Top/Bottom Overlay on PAD
JohnsonMiller , 10-21-2016, 03:06 AM
With overlay on pad we see different output when ordered from two PCB manufactured, first made pad higher priority and removed overlay while second did not and pad is cover with overlay!
First, how we can avoid this issue in design time?
Second, how we can force manufacturer to do modifications?
Third, which software do you recommend to check or edit Gerber files?
mairomaster , 10-21-2016, 03:29 AM
You should use a design check rule for that. Altium for example has Silk screen to solder mask distance rule.
I normally add a manufacturing note that the silk screen should be clipped from pads if necessary. It is a standard manufacturing practice, but it is always better if they have gerbers with no such problems in a first place.
I use ViewMate but it's quite buggy/inconvenient to use in my opinion. It works fine for me since I don't need any fancy features - I just quickly check if each layers looks alright. Even recently I started doing that in the Altium CAM viewer, but I wouldn't recommend it for in-depth checking, since it's zoom option is broken in Win 10. At the time I was looking for a good user friendly gerber view but I couldn't find such. I never need to edit gerbers, I think you should be getting everything right in the EDA. Often the manufacturers we use do some adjustments in the gerbers during the front end egnineering, but nothing major.
robertferanec , 10-23-2016, 05:59 AM
Your gerber data should be designed the way, that PCB manufacturer should not modify them. Otherwise you will end up in situations as you experienced.
Normally we remove all Overlay from pads in our designs. As @mairomaster described, there is a rule for it in Altium:
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