Thank you for all your answers.
Within the last year and a half, we have started embarking on several OEM
products in addition to products we market ourselves. One of the OEM
requirements is to use a tier one contract manufacturer. Previously we have
acted as our own CM - we have the boards fabbed at one place, sent back and
then we send them somewhere else for populating. Our newest products have
no thru hole at all, however many of our older products usually have several
thru hole components, connectors, etc, that we hand install in house.
I joined this forum and started to realize that we have very few controls or
specs in place for our outside suppliers. We just take what they give us.
I am not new to the co. but in a new position to the company, manu.
engineer, and have started to try to clear up some of these glaring holes in
our documentation.
On our production floor, two types of solder wire are typically available -
the Kester 44 63/37 RA core, or a no clean Kester 245 63/37 which is
classified as ROL0. The no clean is typically only used to solder on
shielding cans or connectors that are visible to the customer, because less
cleaning is needed. For any thru hole, in house ECO parts changes, or
installing shortages, the 44 is used. Some of the component lands it is
used on would have had solder paste from the reflow process.
We do hand spot cleaning of the flux with M.G. Chemicals Safety Wash which
is composed primarily of ethanol and methyl alcohol. I have been told by
Kester that the two fluxes mentioned above should not cause any problems
when mixed.
Any further input is appreciated. We do not yet use any BGA's on our
products.
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: June 19, 2001 6:39 AM
To: TechNet E-Mail Forum.; Genny Gibbard
Subject: Re: [TN] No Clean and Rosin core on same PCB
We have CM's that use no-clean solder paste on our PCB's. We have not
given
the CM any spec other than that it be approx. 60/40 tin-lead. In house,
however, for hand assembly we have always used solder such as Kester "44"
RA
core solder. We're working on a new OEM product and the customer has
expressed concerns about mixing the two on the same PCB. We also use a
safety wash board cleaner.
Any thoughts or concerns that we should address?
**Genny, you may have a possible materials incompatibility issue. You do
not say whether the Kester 44 you use in-house goes on the low solids paste
residues from the contract manufacturer. Are they doing the primary build,
with you hand soldering in some final parts in house? Or are you trying to
direct your contract manufacturer what to use in their hand soldering
operation? You say that you have a safety wash process. What are the
chemicals in that wash process and what is the low solids solder paste that
your contract manufacturer is using?
In general, if you can give lots of specifics on the materials and
processes involved, you can get direct answers a little easier. This is a
fine forum and the more you tell us about the background, the better
guidance we can give.
Doug Pauls
Rockwell Collins
(which, after our spin off the end of this month, will be....... Rockwell
Collins. Please hold down the gasps of astonishment).
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