Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Wavesoldering

Adam

#5014

Wavesoldering | 19 January, 2001

To you wavesoldering guru's. When wavesoldering with a selective wavesoldering carrier What causes the white vapor type residues around the areas of the carrier which are exposed to the wave ? My Initial reaction was to high of A Pressure for the spray fluxer and the combination of the air knife forcing the flux beyond the apertures, or even hot air knife. I've tried exercises with these three parameters, but still without any luck . Does Any one know what causes this cosmetis issue and how to avoid it ?

Thanks in advance

Adam

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#5020

Wavesoldering | 19 January, 2001

How did you decide the problem is cosmetic?

One possibility is poorly cured solder mask. Tell us more about your board, flux and solder materials, and wave process.

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JohnW

#5026

Wavesoldering | 22 January, 2001

Yep more information wuld be good.

Although I have seen this type of thing on boards before and if could be flux residues of some sort.

JohnW

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Adam

#5028

Wavesoldering | 22 January, 2001

The assembly is HASL finished. The colour of the solder mask is green, ( sorry I dont know the technical name ).The flux is No Clean (Koki JS3000)which is seeing a preheat temp between 90-100degCel. The solder pot is set at 250degCel and is 63/37.

Thanks in Advance.

Adam

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#5056

Wavesoldering | 23 January, 2001

Sorry, not much help for me there. More information would be helpful. For instance: * Talk about the distribution of the problem, including a single lot or from various lots and over components and component types on the board * Tell us about the board (ie, thickness, type, solder mask, pads coating, pad size, etc) * Describe the component(s) (ie, type, termination finish, etc) * Take us through your process steps that proceed the problem, including the reflow profile and its control * Help us with the solder and the flux you are using

Let�s talk about your residues. For instance: * Where are they located? [All over wave soldered portion, laminate only, solder mask only, solder only, specific components only, etc] * What color are they? [Many "white" residues are actually more gray or yellow, than white] * What do they look like? [milky coating, salty deposit, smooth varnish]

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