I believe that most peoples problems and fears of ENIG don't come from ENIG
it self, it comes from shoddy work with ENIG during/before the Plating
process, not ENIG itself. If the Vendor doesn't maintain the baths properly,
there's issues, if their process is flawed, there's issues. But if they take
care of maintaining the baths properly, and do the plating process properly,
and meet the minimum plating requirements per IPC, there really shouldn't be
an issue with ENIG in most uses. There's a reason why it has the highest
percentage of use on boards that exist around the world today. We use it on
every board we do, for every customer, unless specified to do otherwise, and
we've had no problems from our customers, or from the boards we fab and
assemble for our customers.
To us, the bottom line is, are you using a quality vendor?
But with everyone trying to save a buck, sometimes it cost's you.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Friday, December 01, 2006 8:24 AM
To: [log in to unmask]
Subject: Re: [TN] ENIG Risks
4 uinchs of gold on a 7 sq. in board =28 uinches of gold per board.
100 boards =2800 uinches of total gold dissolved into the solder pot per
month.
Assuming the client has a standard wave solder machine that can hold a
minimum of 1000 lbs of solder, and some drag-out is going to occur, he can
build 100 boards per month for the next ten years before his gold content in
the solder pot exceeds .00011 percent gold.
He will never have a brittle fracture using ENIG on through-hole parts,
unless his pwb design is subject to a tremendous CTE mismatch, in both the
planar axis as well as the z-axis.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Lazzara
Sent: Thursday, November 30, 2006 3:47 PM
To: [log in to unmask]
Subject: [TN] ENIG Risks
Dear TechNetters:
My company recently produced bare PCBs with ENIG finish for a client who now
wants HASL. I can't strip the ENIG and the routed PCBs are too small for
HASL processing (conveyor or dip).
Here's my client's concern:
1. ENIG will poison his solder pot.
2. ENIG will introduce risk of thru-hole component attachment failure
On the poison solder pot issue, my client will only assemble 100 PCBs every
30-days. Each PCB has a total solderable surface area of 6.94 sq."
At an average measure of 4.05uI of gold I can't see the drag-in being an
issue of concern. The small amount of gold introduced to the solder pot will
likely be diluted into nothingness by solder replenishment across the next
30-days.
On the embrittlement issue, virtually everything I find in the TechNet
archives (and elsewhere) concerns SMT designs and applications. Here again
the concern is with an all thru-hole design with no SMDs in the build. If
it's important, the nickel thickness averages 118uI.
Q1: Is there a real risk to solder pot poisoning?
Q2: Is there a real risk that PTH components are going to unplug due to
embrittlement?
Your thoughts and opinions are appreciated -
Robert Lazzara
VP, Business Development
Circuit Connect, Inc.
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