As you are finding problem near the finger, this is my honest solution to you.

(1) Check your flux density and if requires change flux with new one.

(2) Have wave fixtures made as board is bowing in the center and the solder
height is being controlled keeping center in mind such that solder won't
overflow. Because of the bow, area along the fingers is deprived of enough
solder. I believe this is the real cause of the problem.

(3) Also make sure flux is being applied properly by removing the board
before wave. Use solder sample for the purpose so that you can flip to see
flux coverage. Also check your hot air blower that remove flux drops and
help in spreading the flux.

(4) Turn on your turbulent or dancer wave.

(5) Make sure that profile is correct such that max top temp is not
exceeding more than 150C and at the same time top preheat is around 230F. I
have mentioned temp in F and C both.

(6) Increase solder pot temp to 480-500 F

This will surely help and if you still see the problem then check solder
impurity and last resource call flux supplier and then machine supplier.


re,
ken patel


At 12:01 PM 10/15/97 -0400, Blanchet,Richard wrote:
>Sorry if my previous note didn't contain all the info.
>
>I have problems with SOIC 16 tom and SOIC 14 and also with small 0805, 1206
>resistors.
>I'm running at 4.0 ft/min.
>I cannot change the rotation of the board because of the solder theives that
>have been designed to help me. By the way, sometimes the solder theives are
>not soldered. This is not a defect but and indication that something is
>wrong.
>The pads have been designed for wave soldering as far as I know. It's just
>that I get more of this problem near the fingers. Detachable rails would
>surely help but they wouldn't resolve the problem 100% since the problem is
>found elsewhere.
>
>Thank you.
>
> ----------
>From: owner-technet
>To: TechNet
>Subject: Re: [TECHNET] Assy: Soldering on gold plated pads
>Date: 15 October, 1997 10:14
>
>Charles Barker@IO-US
>10/15/97 10:14 AM
>
>Mr. Blanchet:
>
>What kind of components are you having problems with? SOT-23, passive
>chips, I. C.'s? Were the pads on this side of the board designed with wave
>soldering in mind?
>
>Can you rotate the board and send it through the wave in a different
>direction?
>
>What is your conveyor speed?
>
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______________________________________________________
Ken Patel                       Phone:  (408) 490-6804
575 Cottonwood Dr.              Fax:    (408) 490-6859
Milpitas, CA 95035              Beeper: (888) 769-1808

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