How do i get rid of the vias in my solder mask (layer 29 7 30 stop)

On 02/11/2014 01:21 AM, Brian Van Staden wrote:

Hi guys

I'm new to Eagle and battling a bit with creating the Gerber files in

particular the stop mask (layer 29 & 30) what is happening when i

generate the stop mask it give me the vias and the pads on my solder

mask how do i get rid of the vias in my solder mask??

Good morning, Brian,

From the board editor, click on DRC => Masks => Limit.  This specifies

the maximum sized smd/pad/via that gets covered with mask.  Such

features larger than this value have the mask pulled back.

In general, you want the mask pulled back from all holes (set Limit to

0) that are not specifically filled with a material.  The reason for

this is that covering the hole creates an air pocket.  When the board

goes through re-flow, the mask softens and the contained air will heat

up and expand, possibly dislodging a nearby part.  One should also

consider the application's environment and whether the board will

operate at STP, or if it will be exposed to high  (i.e. submersion) or

low ambient pressures (i.e. high altitude or space).

There may be a compelling reason to cover smaller holes, but I can't

think of any at the moment.

The bottom line is that it's a design decision.

HTH,

    - Chuck

 

Regards

Brian

 

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On 02/11/2014 01:21 AM, Brian Van Staden wrote:

Hi guys

I'm new to Eagle and battling a bit with creating the Gerber files in

particular the stop mask (layer 29 & 30) what is happening when i

generate the stop mask it give me the vias and the pads on my solder

mask how do i get rid of the vias in my solder mask??

Good morning, Brian,

From the board editor, click on DRC => Masks => Limit.  This specifies

the maximum sized smd/pad/via that gets covered with mask.  Such

features larger than this value have the mask pulled back.

In general, you want the mask pulled back from all holes (set Limit to

0) that are not specifically filled with a material.  The reason for

this is that covering the hole creates an air pocket.  When the board

goes through re-flow, the mask softens and the contained air will heat

up and expand, possibly dislodging a nearby part.  One should also

consider the application's environment and whether the board will

operate at STP, or if it will be exposed to high  (i.e. submersion) or

low ambient pressures (i.e. high altitude or space).

There may be a compelling reason to cover smaller holes, but I can't

think of any at the moment.

The bottom line is that it's a design decision.

HTH,

    - Chuck

 

Regards

Brian

 

--

To view any images and attachments in this post, visit:

http://www.element14.com/community/message/103406

Hi Chuck

Thanks for the reply I checked to see in the DRC - mask - limits, and it is set to 0 what i red there was that that " stop masks are generated for smds, pads and those vias that have a drill diameter that exceeds limits"  i have tried to check and see where i can change the vias drill size but not sure where, everything is set to default.

Brian