I did not measure it. But corner balls were oblong or not soldered (when
using only flux).
X-ray showed also not soldered balls (round, with circuit pad intact) among
elliptic ones which were soldered. Usually when I see an elliptic shape or
almost a cylindric shape I know that in that area the BGA is higher . When
between two such contacts I see a round one, I know that there is no
contact. I hope that with the Genrad BGA print station we will overcome
this problem, if better profiling is not possible. We don't have spare
boards, each one is very expensive. And no time to play, delivery is
Yesterday. I also think that some of the BGA's beside of the ceramics have
non eutectic balls, Information is hard to get from the supplier. Also,
although Solder paste may induce voiding, I prefer to see acceptable voids-a
sign that the melting took place. With flux only you never get voids
because the component balls don't have any, but you can't be sure if you
reflowed them or not unless they change shape.
Gaby
----- Original Message -----
From: "Earl Moon" <[log in to unmask]>
To: "TechNet E-Mail Forum." <[log in to unmask]>; "Gaby Bogdan"
<[log in to unmask]>
Sent: Friday, May 31, 2002 5:01 PM
Subject: Re: Re: [TN] NTC - The Gregory's are a team now...
> How bad is the coplanarity problem. I'm just waking up my thinking
processes
> and may, wonder of woners, have some ideas for the little Genrad
> contraption.
>
> Earl
>
> ----- Original Message -----
> From: "Gaby Bogdan" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, May 31, 2002 8:27 AM
> Subject: Re: [TN] NTC - The Gregory's are a team now...
>
>
> > Dear Earl,
> > In our country there was a custom to work in the same place till
pension.
> > This is because the size of the country and other factors.Young people
> don't
> > do it any more. I am dedicated to my workplace, spent my youth here, as
> many
> > others, and really love it.
> > I just know everybody, what we are capable of , and I am putting every
> > effort in improving myself and our image dayly. The problem is not our
> > possibilities, but the fact that customers are not easy to aquire. I
hope
> > that we will continue to survive, our managers try hard. But we have
here
> > also a bad political situation right now. And that adds to our fears.
> > Concerning BGA rework, we just bought a manual print station from
GENRAD,
> > and try to overcome with it the coplanarity problems, as well as using
it
> > for ceramic BGA's.
> > They have sent us a formula for the stencil apertures, and the user's
> > manual.
> > In the next few days we will have the opportunity to use it , as we got
a
> > job for 100 parts replacement with new version components. I think that
> > printing paste on the part is easier, if bad ,you clean the part, not
the
> > crcuit. What do you think?
> > Gaby
> > ----- Original Message -----
> > From: "Earl Moon" <[log in to unmask]>
> > To: <[log in to unmask]>; <[log in to unmask]>
> > Sent: Friday, May 31, 2002 8:06 AM
> > Subject: Re: NTC - The Gregory's are a team now...
> >
> >
> > > Gaby, sorry to cut in here but the world is getting smaller as more
jobs
> > are
> > > lost everyday. Steve spoke of my knowledge about immediate, drastic
> > > dowhsizing relative to my having placed orders with SCI in Austin
mostly
> > > because Jason Gregory was there. Immedieately upon receipt of
shipment,
> I
> > > was notified of the plant closing and Jason's lost job, among many
other
> > > fine folks. I'm just thrilled Jason is working again and with someone
of
> > the
> > > same family name and technical ability.
> > >
> > > I now talk with over a dozen displaced folks who's talents and
> experience
> > > are very well known and established. I do alright but not as well as
> last
> > > year before the "crash" - pardon the awful expression. I just hope
> > everyone
> > > does well through this mess. I know you will as you are one of the
best.
> > >
> > > Could you tell me about your BGA rework experience here or off line.
Was
> > it
> > > the process or part?
> > >
> > > Best wishes,
> > >
> > > Earl
> > >
> >
>
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> >
>
>
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