Hi Bob!
You must have had your "Technet Ears" turned off the past couple of
days, because you just missed the same exact thread. I'll paste some of
the traffic below...
-Steve Gregory-
Why the RMA flux?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jones, Evamaria
Sent: Wednesday, March 01, 2006 11:15 AM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
I would add using RMA flux!
Eva
________________________________
From: TechNet on behalf of Dehoyos, Ramon
Sent: Wed 3/1/2006 8:43 AM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
Hi Chris:
It seems that a lot of good recommendations were given. In
summary pretin the connectors, use a spacer if possible, do the
soldering of these parts after oven preheat( 100 C for 15 min) over a
hot plate (125 C), use a hot tip (117) soldering iron and lastly
instruct operators not to touch the pads, but to touch the lead only
with a solder wetted iron tip. This last recommendation is to avoid
lifting pads and burning the butter coat. If you do the last three you
will get more than 75% fill. In a previous we had to solder many metal
body inductors on boards that had top and bottom exposed ground planes
and many inner ground planes. The boards were silver color except for
some pads that were isolated and some pads that were connected to the
top and bottom planes. You may do some contract X ray to prove your
process.
Best Regards,
Ramon
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
Sent: Tuesday, February 28, 2006 3:12 PM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
You may also wish to look at pre-tinning the connector. This sometimes
aids in the wetting of the solder up to the top side of the PWB.
I have also pre-filled this type of connector hole with solder paste and
used a rework machine to reflow from the topside. This really worked
well.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Barmuta, Mike
Sent: Tuesday, February 28, 2006 1:22 PM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
Hi Chris: I think if you look closely at the wording in 6.3.1, 50 % hole
fill is not acceptable for class 3, only class 1 and 2.
Ken is building to class 3.
BTW You are probably looking at IPC-A-610 rev C. The new one is rev D
section 7.5.5.1
Regards
Michael Barmuta
Staff Engineer
Fluke Corp.
Everett WA
425-446-6076
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Schaefer, Chris
Sent: Tuesday, February 28, 2006 11:02 AM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
Section 6.3.1 speaks about a 50% vertical hole fill on sections of the
board that are considered thermal planes or conductor planes. It sounds
like this applies, but it may require something from your customer to
allow this or for reasons of stress it is required - not sure. We have
issues such as your and we have spoken with the customer and have
received the ok to allow a 50% fill versus the traditional 75%.
I agree with the previous point, but it will not allow for any process
anomalies that occur on occasion. If for some reason the connector has
issues related to the solderability, then you have a problem. In another
scenario if the area/ connector has not been proper fluxed or achieved
proper solder contact - it might look fine on the outside, but has not
achieved the solderability levels you desire.
Food for thought...
Have a nice day guys!
Chris Schaefer
Suntron Corporation
Process Engineer
540 N. Rogers Road
Olathe, Kansas 66062
913.393.5878
[log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of John Berg
Sent: Tuesday, February 28, 2006 12:44 PM
To: [log in to unmask]
Subject: Re: [TN] Solder Joint Inspection
If x-ray is not an option, you need to set up a soldering process that
would not require inspection. On a thermally relieved pad that does not
get sufficient fill, you need to preheat the pad area prior to hand
soldering to compensate for the heat sinking. If you can get a dummy
populated board, preheat it to a known reference level, and then remove
the connector body to examine the % fill. Find the minimum reference
preheat that will obtain your desired % fill. If you can't get a dummy
populated board, you can use a few production boards to find the
reference preheat by utilizing an ouitside x-ray service to determine
the % fill.
>>> [log in to unmask] 2/28/2006 7:55 AM >>>
We are having a heck of a time inspecting some solder joints and could
use your help.
Per Class 3 a solder joint is supposed to have at least a 75% fill. We
have a circuit board that has large ground planes and hand soldered
connectors that are impossible to inspect for top side solder.
We do not have access to an x-ray and are wondering if there are any
clever ways to inspect these solder joints.
Thanks,
KennyB
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Arciolla
Sent: Wednesday, March 01, 2006 1:04 PM
To: [log in to unmask]
Subject: [TN] VERTICAL FILL
Good Afternoon,
We are having a problem determining if we are getting 75% vertical fill
on a couple of our boards. We have a transformer that the lead is going
into the plated through hole and the transformer wire is wrapped around
the lead and sitting on top of the hole and we cannot see any evidence
of vertical fill. Any input would be greatly appreciated
Thanking you,
Bob Arciolla
Endicott Research Group
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