Mirror image BGA connectors

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I'm trying to develop a process for a small assembly consist... - Aug 08, 2001 by

Very smooth. First, describe how this thing wowls at the mo... - Aug 08, 2001 by davef

Adam- Mikie here. I too am placing 2 PBGA sockets on an asse... - Aug 09, 2001 by

Thank you Michael, yes we use a Fine Focus X-Ray machine, w... - Aug 09, 2001 by

Adam

#17141

Mirror image BGA connectors | 8 August, 2001

I'm trying to develop a process for a small assembly consisting of two mirror image PBGA connectors, I've built the first prototype, but I ran into different problems: 1. The SMT connector was shifting during placemnt, and I knew one issue i have to deal with is HASSL finish. 2. Opens were found during inspection which I resolved with modifying the aperature on the stencil to get better paste deposit. 3. I also had to tape the secondary side connector, so it would not fall in the oven. The bottomline is the cycle time to build this assembly is not desirable. any takers?

Regards, Adam.

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davef

#17151

Mirror image BGA connectors | 8 August, 2001

Very smooth. First, describe how this thing wowls at the moon. Next, state that process time is so long that you can't afford to make it. Finally, you ask someone to make it for you.

Let's get Mikie to do it. Hey, Mikie ...

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Michael Parker

#17155

Mirror image BGA connectors | 9 August, 2001

Adam- Mikie here. I too am placing 2 PBGA sockets on an assembly but they aren't mirror imaged. Thanks to the SMT Gods for that one.

You say you added more paste to solve for open solder. Do you have x-ray? Were the alignments perfect? Also the part is a big heat sink, did you temp profile under the part? Cold solder could be the cause of the opens.

We use alignment fixtures for the sockets. You would need to add tooling holes to the fab. The little fixtures have a half inch perimeter foot print and the socket is hand placed just prior to reflow.

You might want to consider running the second side on the reflow belt. That way the first socket doesn't have a chance to fall off. (leave the alignment fixture in place for bottom side) You would need to change the profile to mostly top heat only, if you have that control in your oven.

I could provide more details on fixturing if you need it. I am in California, not sure where you are located.

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Adam

#17158

Mirror image BGA connectors | 9 August, 2001

Thank you Michael, yes we use a Fine Focus X-Ray machine, we also had some dummy connectors to play with, so we profiled the board until we reached a desirable profile. For placement we used a GSM machine, the only issue we ran into there is the part will shift during transport on the conveyor due to the uneven surface of the PCB. A fixture is a good idea to solder the otherside, something I need to explore for the next run, and using the Paragon 150 oven, the temperature control will not be an issue. Thanks again for the input.

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Adam

#17159

Mirror image BGA connectors | 9 August, 2001

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