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Blow Holes voids in solder fillet on caps

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#66670

Blow Holes voids in solder fillet on caps | 26 June, 2012

Hello there, I'm presently experiencing some blow holes and solder voids in the solder fillet of caps on boards. They are ceramic caps. The solder is SAC105 and the parts range from 33pf to 0.1uf ceramic. Any suggestions?

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#66683

Blow Holes voids in solder fillet on caps | 27 June, 2012

I'm spinning on this. Are we talking PTH or SMT?

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#66690

Blow Holes voids in solder fillet on caps | 28 June, 2012

I'm sorry. These are SMT caps such as a C0805C271J1GAC. Small 0805 caps. I know they gennerally give you solder balls that sit on the side of those parts but they wash off.

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aci

#66692

Blow Holes voids in solder fillet on caps | 28 June, 2012

blow holes and via holes are almost always caused by moisture and in PTH they could be moisture and improper drilled holes. If you are seeing solder balls next to the parts than I would say you have a reflow profile problem. Are you using any kind of thermal prifiling device to verify? like KIC or mole?

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#66697

Blow Holes voids in solder fillet on caps | 28 June, 2012

Yes I have a KIC and have checked the profile often. I just changed the reel of the parts that are causing problems and it went away. Now what am I suppose to say? I have made an NCMR for the parts but I'm sure they would work in an environment of 63/37.

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#66698

Blow Holes voids in solder fillet on caps | 28 June, 2012

Here’s what we seem to know: * There’s a problem with voiding in the solder connections of SMT capacitors * A void is an open area caused by air or process fluid that is trapped within a solder connection * Voids are an allowable condition as long as the solder connection meets all of the other dimensional requirements * Voids are process indicators * John expects to see solder balls here instead of voids. Solder balls are the first cousins of voids.

Here’s what we don’t understand: * What’s the source of the air or process fluid that’s trapped within the solder joint? * Howcum this is only happening with SMT capacitors?

Things that I’d like to understand better are: * Could the capacitors be outgassing something or other? Does component baking, better moisture sensitivity handling of the capacitors help? * Are there buried vias below the pads of the components that have entrapped stuff that is outgassing during solder processing? * Is the thermal recipe for reflow soldering causing the solder paste to skin-over and entrap flux? [If so, why is this only happening with capacitors?]

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#66701

Blow Holes voids in solder fillet on caps | 28 June, 2012

John: Secure the capacitors that you removed from the machine ... * Removed capacitors have a problem * New replacement capacitors don't have a problem

Find help to determine the difference between the two reels of parts

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