Eagle PCB, Tstop/Bstop on vias?

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I notice in eagle that by default there is a tstop and bstop on all the vias. Can you remove the tstop and bstop on the vias?

What is the advantage of not having a solder mask on the vias? what are the disadvantages?

I would like to have solder masks on all my vias so that there is less chance of the vias accidentally sucking up solder when the unit is put together.

regards,

alan to

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High reliability boards usually have the vias filled with solder, the solder mask would prevent this.

Leon

Leon Heller G1HSM

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Thanks, that makes alot of sense.

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toalan wrote:
I notice in eagle that by default there is a tstop and bstop on all the vias. Can you remove the tstop and bstop on the vias?

What is the advantage of not having a solder mask on the vias? what are the disadvantages?

I would like to have solder masks on all my vias so that there is less chance of the vias accidentally sucking up solder when the unit is put together.

regards,

alan to


You can have your PCBs filled as Leon mentioned - that is part of the fabrication process typically. It's a fairly spendy option. This will prevent solder from getting sucked in.

Vias with soldermask covering them are called "tented vias". Most fabs can do them as part off their standard process. if a via is tented - you (obviously) cannot probe it, or solder to it (without first scratching off the solder mask). However, you are then protected against accidental shorts to that exposed via. It can also be used to prevent solder from getting sucked into vias.

You can also have vias capped. This is where there's actual copper covering the via's hole. This is quite spendy and uncommon.

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In eagle: Check out the value for "Limit" in "DRC: Masks". You can then add tstop and bstop to individual vias by using "change stop on".

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Hi -the value of the tstop & bstop can be changed but this is not recommened as the default setting is usually sufficient for standard pcb manufacturing.

" Tented vias " as mentioned in a previous reply is something completely different and is not required on a basic two layer pcb.

I would recommend that you leave the tstop values as add in add a note when ordering your pcb.

Simply ask for the vias to be covered with soldermask.

Regards:Matthew