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Solder voids in PTH

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#51462

Solder voids in PTH | 18 August, 2007

Hi All,

Via X-rays, we found solder voids appear on PTH location, especially on Dimm connectors area.

We think this should be related to PCB issue as we found solder unable to fill up the PTH hole during bare board testing at wave soldering machine.

This PCB is with immersion silver plating. We change PCB vendor and found similar problem appear..We checked the wave profile, it was within our specification. Confuse..What went wrong..Need help.

Thanks, Learn From U

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#51466

Solder voids in PTH | 19 August, 2007

What are you trying to do: * Improve hole fill? * Reduce PTH voiding?

Hole fill: Search the fine SMTnet Archives for stuff like: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=36063

PTH voiding: Ideally, there are no voids. We're unaware of a specification that defines acceptance of voids in PTH solder connections. * From a reliability stand-point, a PTH solder connection with voids typically has no significant consequence, unless the voids contain chemicals that attack the surrounding metal. * From a mechanical stand-point, the component lead provides superior redundancy in the connection.

And you're using an xray on PTH connections because???? We don't use a ballpeen hammer to crimp the leads of DIP components. Do you?

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dd

#53718

Solder voids in PTH | 19 February, 2008

Do you of reducing hole size of DIMM connector will improve solder voids??

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#53719

Solder voids in PTH | 19 February, 2008

Duno. What's the diameter of: * Finished connector lead * Finished through hole

We reckon: Lead size plus ~0.25mm [0.010"] is normal.

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dd

#53720

Solder voids in PTH | 19 February, 2008

Connector pin - 10.83 mils Hole dia - 27 - 33 mils. We are trying to find the optimam level for hole dia.

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#53722

Solder voids in PTH | 20 February, 2008

We'd go with the formula above.

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#53729

Solder voids in PTH | 20 February, 2008

We had a similar problem with lead-free through-hole components.

We baked those baords to remove the residual moisture and everything went to 100% pass - defect was gone.

Couldnt hurt to try a sample run while you decide if the PCB holes need to be re-engineered.

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#53731

Solder voids in PTH | 20 February, 2008

ni,

I had similar problem too.I bake PCB in SW mashine - about 8h ,T=90 C.Problem is in the base material of PCB - there are moisture in the material.After my complaint to PCB factory , they change material and the problem disappear.

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#53736

Solder voids in PTH | 20 February, 2008

iv40, I don't suppose you know/remember what base material you were using that caused the problem and what material you switched to was, do you?

We just pre-bake all our lead free PCBs as a precuation but I would like to remove the process if I can find the root cause material.

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#53751

Solder voids in PTH | 21 February, 2008

hi,Toni,

we use only FR4.Some of PCB we order in China and Taiwan.With these PCBs we can't any problem.Other PCB we order here in Bulgaria.The problems with voids start last year - we have voids only in PCBs from Bulgarian factory.The process is same , but when we use BG PCB we have voids.Then I talk with our deliverer from BG about the problem.They tell me , that they use base material from China.After that, they changed base material - purchace from Germany, and now all is ok .

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#58735

Solder voids in PTH | 6 May, 2009

We have prob Solder voids for Connector, Micro D. We used HMP solder wire and pcb thickness is 0.093".

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