DRC Doesn't Flag Solder Mask Minimum Pad To Pad Spacing.

[iquacker]

My board house frequently kicks back my fine pitch and leadless designs because the solder mask can't be made to fit between pads that are too close together. I can set my own mask in a footprint by footprint basis, so that small spaces do not have masks, but different fabricators have different minimums. It seems to me that detection of a minimum mask width should be added to the MASKS tab in the DRC.

Regards -

[edwin.robledo]

Hi iquacker,

Thank you for taking the time to post your question in the Autodesk EAGLE forum.  Please consider to set your DRC/Mask - STOP Min/Max to a value of '0'. This should give you the minimum on each pad. 

Let me know if this helps.

Best Regards,

Ed

[iquacker]

Hi Ed,

Good suggestion, but that's not going to work for me. Since I use a number of board houses - each with its own mask width minimum, I would like to put this spec into the DRC and be flagged if violated.  Even better if it could remove the mask for all portions narrower than the entered minimum. This shouldn't be an unusual situation since more and more these days, many of us deal with more fine pitch and leadless parts. 

Regards -

[rachaelATWH4]

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@edwin.robledo wrote:

Please consider to set your DRC/Mask - STOP Min/Max to a value of '0'. This should give you the minimum on each pad. 

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Hi Ed, this would help in some situations, but only when the parts use "auto" mask generation. This generation is too inflexible and applies board wide so you can't set it up to work well for all your different parts. I often have to turn off the mask generation and draw them on manually as part of the footprint.

I think @iquacker has a valid suggestion here, it would be useful to be able to specify in the DRC the minimum mask width which can be achieved by the PCB vendor, and flag violations in DRC. You could then also give the ability to easily remove the mask in these areas if needed by overlaying a larger mask aperture over the area of concern. But of course, improving the mask generation by making it per part configurable without having to manually draw the mask apertures would go a long way towards minimizing these issues too as often they are caused by the lack of fine control in the current auto generation system.

Best Regards,

Rachael