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IR zone vs forced convection

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#44762

IR zone vs forced convection | 30 October, 2006

I have some problems in sufficient preheating the pcb's. They splatter on the mainwave, causing solderballing. Less flux causes problems with the fill of the through- holes.

We use a Delta Wave with 3 preheat zones, the first two are calrods the third is a IR zone. This configuration was advised by our machine supplier.

I begin to have doubts about this configuration, maybe forced convection had been a better option.

Anyone experience with this issue?

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RDR

#44763

IR zone vs forced convection | 30 October, 2006

Are your preheaters maxed out then? What is conveyor speed?

anyway I would not have issue with that configuration at all. I have actually found that when using convection for some watersolubles you actually dry out flux and performance is worse. If using VOC free (water based) fluxes then I would believe that you would want the convection.

Russ

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#44765

IR zone vs forced convection | 30 October, 2006

If you are using VOC free flux, then forced convection preheats are better at evaporating the water. That may be why you're getting the "splatter". Plus, forced convection preheaters are most efficient at thermal transfer. See if you can get one to put just before the wave to replace the IR.

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ronalds

#44766

IR zone vs forced convection | 30 October, 2006

Thank you for your input.

Indeed, I am using a VOC free waterbased flux.

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Loco

#44788

IR zone vs forced convection | 31 October, 2006

Hi Ronald,

We have both, 2x calrod on our leaded delta and calrod/convection on our leadfree, both are IR in 3th zone. Indeed, the forced convection is way more efficient, we can run it at 100deg C, where we would need 300deg C for the calrod for the same result (very roughly). I think you've been mislead by your salesrep, we've been clearly told that for VOCfree (and lead free in general, even), forced convection in the second zone is the way to go.

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