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BGA Rework affected by cold weather?

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#73198

BGA Rework affected by cold weather? | 4 December, 2014

HI, I work for a company in New England and recently had a unusually large number of boards fail after replacing a BGA on them. We use a AirVac DRS25 to remove and replace the BGA witch uses local forced hot air. We usually have at least a 90% success rate doing an average of 15 a week. within the last month we've 2 days a week or two apart were the 3 of the 4 boards failed after rework. Both days happen to be the coldest days we've had so far this year, however all parts and machinery are kept withing our temp and humidity controlled building. Also all solder joints apper good through X-Ray and prism camera inspection.

Has anyone herd of something like this before and/or have experience with this type of failure?

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Rob

#73202

BGA Rework affected by cold weather? | 5 December, 2014

Hi Rob,

Could be moisture getting into the boards or the BGAs or it could be drafts messing with the thermocouples measuring the heat at board level meaning you over cook it.

Are you pre-baking the PCBAs & the BGAs before reworking and replacing?

Rob.

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#73204

BGA Rework affected by cold weather? | 5 December, 2014

Hi,

Do you observe any part warping in the corners? Do you X-ray 3D? I really doubt that all joints are fine and the part wouldn't work, but if so, your problem should be part related.If you have a temperature controlled facility I wouldn't even think about the weather outside. I would go in this order:

1. X-ray in a 3D machine and check for opens or cracks in the joints(that will cover the humidity issues). 2. Check your machine profile to make sure everything is in specs. also check your paste, stencils, flux if they are not expired or having some issue. 3. Focus on the part. Try part from another batch or try another vendor.

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#73233

BGA Rework affected by cold weather? | 15 December, 2014

As was stated, there are a number of variables that could come into play. I have used AirVac DRS26 and SRT Machines. We are now using Shuttle Star which has IR as well as hot air heat. This works much better for us. You can view these at. http://www.pcb-repair.com/

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