Hi Haviv,
I really appreciate your reply. I'm glad I have the mechanical samples.
Best regards,
Steve
On Wed, Jun 6, 2018 at 11:18 PM haviv gendelis <[log in to unmask]> wrote:
> Don’t see any problem. The weight per ball is 0.012gr.
> Assembled this components with no shorts.
> Critical to drill the PCB under the component for thermal probe position.
> Pick temperature on the central balls 230-235C.
> Stencil 4-5mil.
> Pad (1mm pitch) 16 mil.
>
> Sent from my iPad
>
> > On 7 Jun 2018, at 2:20, Tan Geok Ang <[log in to unmask]> wrote:
> >
> > Hi Steve,
> > As you stated shimming is one of the methods and another way is to
> reduce the stencil opening dimension/ solder paste volume but this will
> lead to whether is it a cleaning or non cleaning process. If cleaning
> process, whether how effective it is.
> >
> > GA Tan
> >
> >
> > ________________________________
> >
> > From: Steve Gregory <[log in to unmask]>
> > Date: 7 June 2018 at 6:14:10 AM SGT
> > To: [log in to unmask] <[log in to unmask]>
> > Subject: [TN] High Ball Count BGA's with heavy heat spreader
> >
> > Hi All,
> >
> > I've been one of the lucky ones who hasn't had to deal with high ball
> count
> > BGA's (1900+ balls) until now. I have a 1936-ball BGA that we are looking
> > to assemble. I was able to get a couple of mechanical samples so that I
> > could use them to dial my reflow profile in. When I got them, if I said I
> > was surprised, that would be an understatement. This thing weighs close
> to
> > an ounce with the heat spreader (23.133-grams):
> >
> > http://stevezeva.homestead.com/1936_Ball_BGA_with_Heat_Spreader.jpg
> >
> > So I remember reading threads on the Technet about shimming heavy, high
> > ball count BGA's in the corners with something to keep the weight from
> > squishing the balls out and causing shorts, I know that can happen
> because
> > I have seen it on 1152-ball CBGA's from Xilinx.
> >
> > Is there anybody willing to share some tips about assembling these
> beasts?
> > At least I have a couple of mechanical samples I can play with before I
> > dive in with live product....these are spendy.
> >
> > Steve
> >
> > --
> >
> >
> >
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--
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133
--
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