Hi Rudy:Last time I checked 10 microns = 0.4 mils :)
Anyway the 5-15 micron thickness(0.2-0.6 mils)sounds like
a thickness for fused Sn/Pb final solderable finish,too
much for an etch resist.We plate about 2 microns or 0.08
mils.
Regards
Michael Barmuta
Staff Engineer
Fluke Corp.
Everett Wa.
(206)356-6076
On Sat, 26 Oct 1996 15:50:50 -0700 [log in to unmask] wrote:
> From: [log in to unmask]> Date: Sat, 26 Oct 1996 15:50:50 -0700
> Subject: Re: FAB: Tin Lead etch resists (fwd)
> To: [log in to unmask]
> Cc: [log in to unmask]
>
> In a message dated 96-10-25 18:06:59 EDT, you write:
>
> >What is the minimum acceptable tin/lead etch resist thickness useable in
> >practice? We have people using anything from 5 to 15 microns and
obviously
> >need>to get people to use a minimum thickness to minimise waste and
> treatment
> >costs as>well as environmental impact.
>
> 10 microns = 2.5 mils is about the minimum standard in the US, but the
> practical minimum is determined on a shop by shop basis, and is a function
of
> plating speed, which in reality determines throwing power, (thus slower
> plating=more uniform deposit=lower minimum plating required) and uniformity
> of current density over the boards being plated.
>
> >How practical are lead free/or reduced lead alternatives e.g. pure tin?
> >
> Very practical, and in the US, pure Tin is now the prevalent etch resist.
>
> >What options are there for tin/lead stripping solutions that might be
> capable
> >of>recycling the dissolved metals?
>
> Anything is possible, if the financial incentives are present (which they
> are, at least currently), and the government bureaucrats are not.
>
> However, given the state of the PCB fabrications industry (Which,
summarized,
> can be described as "If you don't like the way things are being done now,
> wait 3 months, they will change), a business person would be better off
> putting money into roulette than investing in a major metals recycling
plant,
> which depended on spent Tin, or Tin/Lead stripper as a raw material.
>
> Rudy Sedlak
> RD Chemical Company
>
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