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BGA Alignment

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Al

#66232

BGA Alignment | 30 April, 2012

We use a small surface mount connector that has two alignment pins to ensure proper alignment. It works fairly well. I'm thinking that this simple alignment solution might work well with lead less parts like a BGA or QFN. I can hand assemble QFNs fairly well but getting proper alignment can be a challenge. A couple of alignment pins on the part and a couple of alignment holes in the PCB cell would make alignment easier.

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#66243

BGA Alignment | 1 May, 2012

Good luck with that.

A couple of things to think about ... * BGA self-align during reflow, just get 'em on the pads * Add a box [or four corner] legend on the bare board to help you position BGA

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Al

#66247

BGA Alignment | 2 May, 2012

The surface tension of lead free solder alloys doesn't self align as well as it does with leaded alloys. Taking the guesswork out of alignment would negate the need for expensive split vision systems and make the parts hand reworkable.

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#66248

BGA Alignment | 2 May, 2012

I don't think hole alignment (registration to the copper layer) would be good enough for QFN and uBGA packages.

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Al

#66250

BGA Alignment | 2 May, 2012

It might get us closer than the "four corner" or "box" legend suggested above. The surface tension of the meniscus should help pull us in.

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aj

#66253

BGA Alignment | 2 May, 2012

Are you having problems with alignment of BGA's or perceiving that you will have problems.

We run thousands and they re-align very well with leadfree if slightly off -

Do you handplace all your BGA's? I would imagine there would be cosiderable cost involved to get the BGA manf to add location pips to the parts and I would suspect that they would not do it anyway....

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Al

#66256

BGA Alignment | 3 May, 2012

I'm thinking of rework, not production. In order to rework the part you have to have an expensive split vision alignment system. A simple standard change would eliminate the need for an expensive system.

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aj

#66280

BGA Alignment | 8 May, 2012

why not use the placement machine to place the BGA again?

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Al

#66291

BGA Alignment | 9 May, 2012

I don't have a placement machine available that will do the job reliably. An Air Vac DRS25 would work well if I had one but I can't afford it. A simple change to the part and cell would allow anyone to rework these parts without expensive equipment.

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#66297

BGA Alignment | 9 May, 2012

I'm with Dave on this one. In my opinion, it'd be much more cost effective to add an alignment legend. Speaking from experience, as I've hand placed many BGA's, all you really need to do is hit the pads. Even with Pb Free Chemistries, the part should self align. And I'm not even sure where you'd put alignment pins on the bottom of a BGA. And considering the artwork on the PCB required for a BGA, QFN, LGA or CSP component, where would you put the alignment holes on the board?

My 32 cents...

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#66776

BGA Alignment | 7 July, 2012

Hi Davef ... I had been beginning for little time to work with rework station infrared, but I have a series of doubts to disclose.. could you help me?

I have a Honton HT-R490 infrared Chinese station, stò trying to climb on a camera zoom lens to align up micro and small bga type mobilephone. 8x 8 mm of greatness, therefore very small. I also thinking about trying to adapt with a project, that I have not created yet, to mount on a system alignment optic video, purchased even by company that she builds station furnished already of optic alignment. these are the my questions: 1 - someone of you has ever tried to make a project "do it yourself" of optic alignment bga, on station infrared? 2 - to line up small bga with measure 8X8 mm what I must do? 3 - as I do to find the correct curve temperatures template of small bga "as mobilphone component." Can you help me?

I premise , that the project that I think of the optic alignment, must have done to hand, not automated, therefore I need alone the optic part to apply to the bar that the lamp sustains infrared... it is a twisted discourse, a few because I don't speak very well the English, but I see that in this forum very technical and prepared people comes, if you have questions or doubts, please ask me

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