0.15mm copper plane clearance from pad is too small?

[cupoftea]

Would you agree, that if hand soldering components, then having the solder resist covered copper plane just 0.15mm away fron the rest ring of a PTH pad (different net) to be soldered is too small for hand soldering? The solder resist would get melted up and could cause opens?
Or, would you agree that there could be shorts from pad to copper plane, even though the plane copper is covered in solder resist?

 

[barry]

Nope. I disagree. It depends on the skill of the person soldering. And melting soldermask is not going to cause opens,

 

[cupoftea]

...thanks, if the melted up solder resist gets into the solder joint?

 

[FvM]

You are asking about industry standard solder mask, not some dubious DIY mask? It does not melt.

0.15 mm pad to plane clearance is O.K. for low voltage, provided you have state-of-the-art photo processed soldermask technology (0.05 - 0.075 mm enlargement, sufficient position accuracy so that the plane copper can't be exposed. I'd nevertheless go for 0.2 to 0.25 mm clearance if PCB density allows for.

 

[cupoftea]

Sorry i forgot to stress that i mean the solder resist melts when hand soldering , as oppose to SMD bath.

...for example, if you turn your solder iron up to 400degc, then shove it into the solder resist, it will go all sticky and gooey, then set hard in a funny shape when you remove the iron....thats what i mean by "melting".

 

[FvM]

You mentioned hand soldering, 400 °C wave solder is absolute no go. Except for extreme cases, it's inappropriate to hand solder at 400 °C. But even at 400 degree, I don't see solder resist melting, FR4 starts to delaminate, however.

 

[cupoftea]

thanks, but i think we would agree that if a hand soldering iron, at 400degc, was pushed against a PCB covered in solder resist, then when you remove the soldering iron, you can see where the solder iron has been...since the solder resist wont be smooth any more, it will be deformed (possibly my use of the term "melting" was inappropriate)

Now suppose that we are trying to hand solder a component to a pad that has a solder mask oversize of just 0.15mm.....then we can see that the solder tip may inadvertently touch against the solder resist near the pad, and impinge on the pad a little bit (the deformed solder resist may find its way onto the pad)...making the pad harder to solder.

 

[barry]

Are you trying to win a bet? Did someone assert that 0.15mm is adequate, and you want to prove them wrong?

If it makes you feel better, just use .25mm.

A skilled technician, with the proper tools, can hand solder with .15mm clearance.