Thank you for responding. Let's see, we screen print the boards. We
sometimes convection reflow, sometimes IR (depending on circumstances). The
boards do have back metal. The size ranges from 2" x 3" to 5" x 7". The
profil seems fine, according to man. specs (Kester Solder- 63/36/2% silver).
Does this help? Thanks.
> -----Original Message-----
> From: Ingemar Hernefjord (EMW) [SMTP:[log in to unmask]]
> Sent: Tuesday, September 21, 1999 8:20 AM
> To: [log in to unmask]
> Subject: Re: [TN] solderability of PTFE Taconic material boards
>
> Jason,
> you don't say what mounting you have, screen-printed or dispensed solder,
> and nor the reflow method, if you have back metal and size of boards, so
> it's not easy to get an image of your product, however we have used
> Taconic, Arlon and others for two decades with some few soldering
> problems. We use Gold Flash over Nickel over Copper conductors, then
> solder print, P-P and reflow in heat conveyor ovens. I can imagine some
> causes for your disaster: a)too thin tin plating b)oxidized nickel under
> tin plating c)porous nickel plating d)wrong soldering profile. You have
> to sort out what step makes problem and then we will help you further,
> ain't easy chap. Little help when the coffee is already boiling away, but
> get Klein Wassink's book 'Soldering in Electronics', you will sleep with
> it under your pillow, I promise!
>
> Ingemar Hernefjord
> Ericsson Microwave Systems
>
> Hello all you technetters,
>
> Question for all the "high-freq" guys out there.
> We have been building PTFE boards quite some tme and a long-running
> problem
> has been the solderability of these boards. They are .018" thick and are
> used for high frequency applications. The spec is for tin immersion
> plating.
> No matter what reflow profiles I use, there are non-wetting signs all over
> the board. The solder just won't flow properly on the pads. It looks as
> though the solder flows, then stops. I've eliminated surface contamination
> by washing the boards prior to build and still the same problem. Are there
> any other platings available that will promote flow and won't affect high
> freq reliability. Please help. Thanks.
>
> Jason Gregory
> Process Tech
> Tadiran Microwave Networks
> (281)263-6671
> [log in to unmask]
>
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