Ryan,
Solder paste vendors has a rule that says:
At least 5 balls must fit inside stencil apertures to have a good solder
paste release. ( good "brick" )
<<...>>
Based on that rule they recomend type 4 for ultra fine pitch, very
probably they conducted a laboratory experiments to achieve this conclusion.
Thanks
Jorge Dourado de Santana
Maintenance / Process Engr
Microtec - Brazil
> -----Original Message-----
> From: Ryan Jennens [SMTP:[log in to unmask]]
> Sent: 14 de Maio de 1999 18:21
> To: [log in to unmask]
> Subject: [TN] FW: [TN] FW: Fine Powder Solder Paste
>
> -----Original Message-----
> From: Ryan Jennens [mailto:[log in to unmask]]
> Sent: Friday, May 14, 1999 5:21 PM
> To: [log in to unmask]
> Subject: RE: [TN] FW: Fine Powder Solder Paste
>
>
> Thanks, all, for the responses. I was wondering if the type 4 paste would
> have value at pitches below 20 mil, say around 12 or 16. If all I will
> get
> is more oxidation and worse release, does it offer any other advantages
> besides sharper corners and straighter sides on its deposits?
>
> -Ryan Jennens
> TelGen Corporation
>
> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]]
> Sent: Friday, May 14, 1999 4:15 PM
> To: [log in to unmask]; [log in to unmask]
> Subject: RE: [TN] FW: Fine Powder Solder Paste
>
>
> Hey Ryan,
>
> As far as 20 mil printing is concerned I would say type 3 i.e (-325/+500)
> should be ok. If you go for type 4 ( i.e -400/+500 ) it has some issues
> like
> the particle size getting smaller will increase the surface area exposed
> to
> oxidation affecting the soldering quality. Also it would be expensive than
> type 3.
> If you are laready printing 20 mils with type 3, why you want to switch to
> trype 4?
> As far as more mass is concerned the volume of the paste will remain same
> irrespective of particle size.
>
> Thanks..
> Ashok
> SMT Engineer
> Solectron Corp.
> Milpitas
>
> > ----------
> > From: Ryan Jennens[SMTP:[log in to unmask]]
> > Reply To: TechNet E-Mail Forum.;Ryan Jennens
> > Sent: Friday, May 14, 1999 11:11 AM
> > To: [log in to unmask]
> > Subject: [TN] FW: Fine Powder Solder Paste
> >
> >
> >
> > -----Original Message-----
> > From: Ryan Jennens [mailto:[log in to unmask]]
> > Sent: Thursday, May 13, 1999 11:51 AM
> > To: TechNet
> > Subject: Fine Powder Solder Paste
> >
> >
> > What stencil design guidelines differ when one decides to go with
> >
> > a -400/+500 particle size solder paste? The paste companies tout
> > that the
> >
> > finer particle paste offers print improvements below 20 mil pitch.
> > But I
> >
> > believe one would have to reduce the aperture sizes all around
> > because more
> >
> > metal would be deposited in each one. Is this accurate? How much
> > reduction
> >
> > is needed. Is home-plating the apertures even more important? I
> > could not
> >
> > find this topic in the archives. We are considering switching for
> > our
> >
> > finer-pitch boards, as their pitch decreases, if it really offers
> an
> >
> > advantage. However, we have been printing 20-mil for a long time
> >
> > with -325/+500 paste for quite a while.
> >
> > -Ryan Jennens
> >
> > TelGen Corporation
> >
> >
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> To subscribe: SUBSCRIBE TechNet <your full name>
> To unsubscribe: SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
> section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> ################################################################
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
