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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


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BGA | 25 February, 2010

We are a small Contract Manufacturer and have received a project which has BGA's on top & bottom. 2 larger BGA's on one side (~_20x20mm) & 3 smaller BGA's (~_8x8mm) on the other. we plan on running the side with the smaller BGA's first but need some advice as to how to keep the 1st side BGA's from falling off when running the second side. Any advice would be helpful. Thanks

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BGA | 25 February, 2010

Good Afternoon Duane,

Surface tension should be adequate to hold the smaller BGA's during second side reflow. You will need to ensure that nothing comes in contact with the parts during reflow. I have added a chipbonder adheasive at the edge of some BGA's that were heavy but you should not have any problem with 8X8 mm.

Good Luck


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BGA | 25 February, 2010

We agree with CL in the above posting. We talked about this previously here on SMTnet. Search the fine SMTnet Archives to find threads like:

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BGA | 1 March, 2010

Good morning Chris, We had discussed surface tension but were not sure if that alone would be enough, so I reduced the bottom side temperature in the oven by 20 degrees to see if that would help. I will be checking results this morning. Thanks for the reply all. Duane

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BGA | 1 March, 2010

I don't think I would reduce the heat at all if there is no vibration in your oven or on the chain you should have no problem with them falling off or moving but you sure don't want a cold solder joint you no the solder joints are so easy to see good luck

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BGA | 2 March, 2010

So Far, so Good. Solder looks real good. Thanks

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BGA | 4 March, 2010

Hi, Duane,

Why don't you try Tacky Flux /Tacky paste flux?

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BGA | 5 March, 2010

How is that going to help hold a BGA to the bottom of the board during secondary reflow?

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Reflow Ovens thermal process improvement

2-Part Mixing Pump