Pratap,
Thanks for the suggestion, but there is very little
clearance on each side of the hole to the SMT locations. Even 1/8" tape
(which would be extremely difficult to handle in a water soluble format) is
too wide. That's why we're having issues with manual dispense of aqueous
mask. Steve's idea of rigging together paint masking plugs is also
impractical due to the small size of the holes (.035) and the hole pitch
(.100). Also these types of plugs are made of silicone or neoprene, which is
too 'mooshy' to stay in the holes. I know these DIP/SIP masking forms exist
(or at least they used to). Joe McKenzie, the founder of Flextronics,
developed what may have been the first mass-marketed ones when I worked for
him in the mid-70s. They were molded out of a high-temp nylon and could go
through hundreds of wave excursions without breaking down. However, Joe
departed this earth a few years back and I don't know if anyone carried
these products on or brought them out under a different company.
Mike McMonagle
PCA Process Engineering Supervisor
K*Tec Electronics
1111 Gillingham Lane
Sugar Land, TX 77478
(281) 243-5639 Phone
(281) 243-5539 Fax
[log in to unmask]
> -----Original Message-----
> From: rampinc [SMTP:[log in to unmask]]
> Sent: Thursday, November 11, 1999 5:34 PM
> To: [log in to unmask]
> Subject: Re: [TN] DIP/SIP Masking
>
> Michael,
>
> My suggestion will be that you use water soluble tape to protect your PTH
> pattern at
> the bottom side. The tape dissolves during water wash cycle of cleaning.
> Give me a call
> at the number listed below for more details about the process and how tape
> can be used.
>
> I used it successfully at IBM few years back ( now I am retired and
> building a web site
> with PCB process information). Will be happy to help.
>
> "McMonagle, Michael R." wrote:
>
> > I have an application where I need to mask off a through-hole
> SIP
> > through wave solder. Washable liquid mask is getting on closely adjacent
> > bottom-side SMT components, and I can't justify an automated dispenser
> with
> > current volumes. I remember a company back in the days of when
> through-hole
> > was king (waaaay back there) that made high-temp filled plastic masking
> > thingamajigs that fit standard DIP/SIP patterns. You just dropped them
> in
> > the hole pattern before wave, then removed and reused them after wave.
> > Anybody out there know what I'm talking about, and who makes them?
> >
> > Mike McMonagle
> > PCA Process Engineering Supervisor
> > K*Tec Electronics
> > 1111 Gillingham Lane
> > Sugar Land, TX 77478
> > (281) 243-5639 Phone
> > (281) 243-5539 Fax
> > [log in to unmask]
> >
> > ##############################################################
> > TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for
> additional
> > information.
> > If you need assistance - contact Gayatri Sardeshpande at [log in to unmask]
> or
> > 847-509-9700 ext.5365
> > ##############################################################
>
> --
> ____________________________________
> Regards,
> Pratap Singh
>
> Tel./Fax: 512-255-6820,
> e-mail: [log in to unmask] or [log in to unmask]
>
> ##############################################################
> TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for
> additional
> information.
> If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
> 847-509-9700 ext.5365
> ##############################################################
##############################################################
TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################
|
