One recommendation (from the learning curve within my company)
        if you have board outlines that include unpopulated locations,
        do your solder stencil such that it doesn't put paste down in
        those unpopulated areas.  It makes visual inspection a little
        easier. The inspectors can immediately recognize the location as
        a Do Not Install (DNIs we call 'em) so they don't write the
        location up as a missing component.

        Also, if you CAN, putting solder paste down on locations that
        are populated at a later hand assembly helps solderer a bit by
        having a layer of existing solder so they don't have to overcome
        the gold/component interface.

        Jan Pelchat


______________________________ Reply Separator _________________________________
Subject: Re: [TN] HASL v/s OSP
Author:  Kelly Kovalovsky <[log in to unmask]> at 0UTG0ING
Date:    8/6/98 3:14 PM


We typically receive no cost reduction from the PWB manufacturers for switching
from HASL to OSP or vice versa.  This applies in a general case. If there is a
particular advantage to the supplier to get away from solder (say you have a
very stringent requirement of no solder on the gold contacts of a board) then
you may get cost advantages in isolated cases.

In the case of the assembly house, it depends. It depends on how much better
your yields get with the advantages (flat solderable surfaces) of the OSP. Or
how much worse your yields get with the OSP. (handling and storage related
issues)

There is some Assembly process learning curve with the OSP, but in my opinion,
if you are going to start working in the 0.020" pitch SMT and under arena, you
should get on the curve.

Kelly Kovalovsky




[log in to unmask] on 08-06-98 01:27:38 PM
Please respond to [log in to unmask]
To: [log in to unmask]
cc:
Subject: [TN] HASL v/s OSP


Fab/Assembly Expert:
I have two questions related to price reduction if I change my pcb surface
finish from HASL to OSP coating (Enthone CU106A).

(1) How much price reduction (in terms of %) can I expect from fab house?
(2) And also how about cost reduction from assembly house?

You can provide me the range if number of layers matters.

re,
Ken Patel
______________________________________________________
Ken Patel                       Phone:  (408) 490-6804
1708 McCarthy Blvd.             Fax:    (408) 490-6859
Milpitas, CA 95035              Beeper: (888) 769-1808

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