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Coolingproblem in reflow profile

Joris Groot koerkamp

#34907

Coolingproblem in reflow profile | 13 June, 2005

For the lead free reflow process we tested with our Vitronics 500smr oven. To reach the high temperature of the lead free profile was no problem. We are not using an active cooling system so the pcb's are maby to hot wen the leaving the oven.

Can anybody tel me if it is possible to use a reflow oven without active coolingzone in the leadfree process?

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peter ng

#34961

Coolingproblem in reflow profile | 14 June, 2005

It's impossible to do so.The cooling phase is important to perform the strength of the solder joint.Without this phase,the good solderbility will not able to achieved.

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GS

#34965

Coolingproblem in reflow profile | 14 June, 2005

Hi Peter, which should be the best cooling rate once belove TAL by using L-F alloy ie. SAC 305 ? Tnks GS

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#35014

Coolingproblem in reflow profile | 16 June, 2005

Cooling may require muff fans positioned over that output conveyor of the oven.

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#35015

Coolingproblem in reflow profile | 16 June, 2005

Peter: Please explain: * You say, "The cooling phase is important to perform the strength of the solder joint." [We agree that fast cooling rates produce fine grain in solder and that fine grained solder connections are stronger than coarse grained. We thought that the destinction between coarse or fine grained solder connections was meaningless because the grain of all connections coarsened over time to be equal in a few months.] * You say, "Without this phase, the good solderbility will not able to achieved." [We thought that "solderability" related to the condition of the surfaces being soldered. It will solder, if you have: Solderable surfaces. Sufficient heat for the correct amount of time. Proper selection of flux and solder.]

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#35040

Coolingproblem in reflow profile | 20 June, 2005

Contact your paste supplier and see what they say. My information on SAC 305 FROM MY SUPPLIER was - "The cool down rate is not as critical for Pb-free solder joints, as it was for SnPb. The grain sizes do not differ is size in the Pb-free bulk solder until you get to a cool down rate much greater than 6 degrees per second. I would attempt to get a cool down rate between 2 and 4 degrees C per second."

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GS

#35056

Coolingproblem in reflow profile | 21 June, 2005

Darby and Dave, many thanks. Regards GS

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Reflow Oven

reflow oven profiler