Karen,
   I could not agree more.   Currently one of our major headaches is the
issue of PCB cleanliness from our suppliers.  Using a solution (75% DI /
25 % IPA) heated to 140 F and a spray cycle of 15 minutes, we have
some PCB Manufacturers supplying product at <2 ug / sq in , several in
the range of 15 - 20 ug / sq in and some in the range of 25-35 ug / sq in.
The middle group causes us many hassles, and the latter is simply
intolerable.  The fact that we get product at <2 shows that it can be done
if the suppliers WANTS to.  As long as tap water is the wash medium
and the cleanliness testing is the cold, < 4 minute test you mentioned,
they might as well be doing no testing at all and stop wasting their time.

>>> Karen Tellefsen <[log in to unmask]> 01/24/98 12:12pm
>>>
Mark Simmons wrote:
> Some of the advantages to HAL are:
> 1.  Solderability.  Nothing solders like solder.

Absolutely, probably HASL best advantage.

> With respect to Cleanliness, <3 mg. cl. sq. in. is routine on modern
> equipment.

You'd probably get < 3 mg Cl/in^2 even if you clean in ice cold tap
water for 5 seconds.  (m = milli)

However, 3 micrograms Cl/inch^2 on HASLed boards, while do-able with
modern PC fab equipment, is hardly routine except for the best
fabricators.  That is unless one measures ionic contamination with an
unheated Omegameter with a test time < 4 min as is done by many PC
fab shops.  A lot of HASLed boards are pretty dirty, ionically speaking.

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