Can anybody supply contact no.
ashok
> ----------
> From: John Bushie[SMTP:[log in to unmask]]
> Sent: January 23, 1998 9:18 AM
> To: [log in to unmask]
> Subject: Re: [TN] Stencil Aperture Shapes -Reply
>
> Hello Everyone,
>
> Jerome Yeo had indicated that using N2 during his reflow soldering
> process improved yields but
> was not used due to price constraints. There are Nitroen generators
> that use a diffusing
> membrane which will allow fast gases such as oxygen to pass from the
> membrane and will produce a
> varying purity of N2 depending on flow rate, pressure and nitrogen
> generator size. All of this
> is produced from compressed air from in shop compressors (easy if you
> already have them).
>
> I have used these systems for other applications and have found them
> very useful for producing
> large volumes of N2 cost effectively.
>
> The one company I am aware of that manufactures this equipment is
> Balston, Whatman Filter
> Systems Division. The units are not cheap starting at several grand
> US but if you need N2 in
> volume and don't like moving tanks, or cylinders around this is a good
> solution.
>
> Regards,
>
> John Bushie
> Taconic ADD
> --- On Tue, 20 Jan 1998 10:08:14 +0800 Jerome Yeo
> <[log in to unmask]> wrote:
> Clinton Windsor,
>
> My process engineer has reported seeing solder balls around the
> components after solder reflow.
> He is running this particular board in a no-clean process using
> Alphametal LR-725 solderpaste, HASL PWB and without N2 at reflow.
>
> Experiments show that turning the N2 on reduces the solder balls
> dramatically.
> However, due to cost constraints, it is necessary to run without
> N2.
>
> Is this the " squeeze balls " that you mentioned ?
>
> Matthew,
>
> Can you fax me the aperture shape definition ?
> My fax number is 011-604-5064447
>
> Thanks.
>
> Jerome Yeo
>
> [log in to unmask]
>
>
> > -----Original Message-----
> > From: Jay DeKing (EMA) [SMTP:[log in to unmask]]
> > Sent: Tuesday, January 20, 1998 12:50 AM
> > To: [log in to unmask]
> > Subject: Re: [TN] Stencil Aperture Shapes -Reply
> >
> > Matthew,
> >
> > Please fax me the paste aperture shape definition. My fax number is
> > (716)334-3481.
> >
> > Thanks,
> >
> > Jay DeKing
> > EMA Mid-Atlantic, Inc.
> > (716)334-2970 voice
> > (716)334-3481 fax
> > [log in to unmask]
> >
> > -----Original Message-----
> > From: Matthew Park [SMTP:[log in to unmask]]
> > Sent: Wednesday, January 07, 1998 11:37 AM
> > To: [log in to unmask]
> > Subject: [TN] Stencil Aperture Shapes -Reply
> >
> > Mr. Windsor:
> > Post your fax number, so I may fax you a solderpaste
> > aperture shape that I use for the complete elimination of
> > solderballs for chip components. It was proven it works
> > better than home plate shape.
> >
> > regards
> > Matthew Park
> >
> > >>> Clinton Windsor
> > <[log in to unmask]> January
> > 7, 1998 1:27 am >>>
> > Dear Technetters,
> >
> > We are trying to eliminate the occurence of solder balls in
> > our
> > production line by trialling various aperture shapes and
> > reductions on
> > the screen printer stencil. The nature of the solder balls
> > suggests
> > that paste is being trapped under the component and then
> > forms a solder
> > ball which adheres to the side of the component. I have seen
> > this type
> > of solder ball referred to as a "squeeze ball". We have tried
> > the so
> > called "home plate" (trapezoidal) shaped apertures with
> > considerable
> > success on nearly all the components except for the 0603
> > capacitors.
> >
> > I would be interested to hear any ideas or suggestions of
> > other aperture
> > shapes or designs which could help solve this problem.
> >
> > Thanks in advance,
> > Clinton Windsor
> >
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>
> ---------------End of Original Message-----------------
>
> --------------------------------------------------------
> Name: John Bushie
> E-mail: John Bushie <[log in to unmask]>
> Date: 01/23/98
> Time: 09:06:18
>
> This message was sent by Z-Mail Pro - from NetManage
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