tStop layer misaligned

seems very bad!

What happens when you run DRC (with layer 29 enabled)?

Fred W...

     Thanks for your prompt attention to this problem.

After a few hours of thinking, observation and research...  but mainly GOOD LUCK... 

I discovered the problem originated in the LIBRARY !!!... 

This is what happened... 

I got the device/package from an original Library from NXP, for the SOT1220 package...

and this had the MISPLACED tStop mask in it...

BUT BECAUSE EAGLE Cad has the "tStop" layer OFF by default ( while editing the package), I was unable to discover this error originally.

The problem is now fixed... but it cost me a few hours which I could have saved if the suggestion below is implemented

SUGGESTION:

   Please make the "tStop" layer ON by default in both the Library editor and Layout editor...

   It will go a long way towards eliminating problems like mine,

   as well as helping the original "designers" of library packages to check their work before distributing to the community.

The original library that (still) contains the error ( pck SOT1220) is...

https://github.com/Sns22/Eagle_PCB_Libraries/blob/master/NXP-libs/nxp_60.lbr 

Hooray!!

Thanks for pointing out the specific library that still contains the error.

element14Dave  Please make sure this library gets fixed and the other suggestions are taken into consideration.

Many third party libraries (it is unclear where this one was sourced from, the github content creator mentions it was compiled from multiple internet sources, but doesn't say which) have errors, so just as a suggestion it is best to have a system in place if third party libraries are going to be used (many people do not use third party libraries) or regardless.

The workflow should include using a third party viewer (there are free or paid options)  to examine the CAM output, because this would have revealed the issue. This is a standard part of my workflow (I don't use third party libraries).

By using a third party viewer, I feel I've gone a long way toward confirming the machine file output interoperability because the board factory will also be using third party software.