Hi S.,

a)      - improper profile (time/heat) 
        - not enough flux
        - improper flux for the oxydes
        - metallisation problems
        - mismatch ( must be very mismatching ) of hole and lead	
        - ...
b) If it´s really insufficient (IPC 610 ?)--> rework
c) It would help if it is a)1
d) Yes
e) Yes

I think you need to profile for each joint like you would doing
handsoldering, that´s IMO the trick with robotic soldering.

Wolfgang

-----Ursprüngliche Nachricht-----
Von: S. Miller [mailto:[log in to unmask]]
Gesendet am: Mittwoch, 30. Mai 2001 13:39
An: [log in to unmask]
Betreff: [TN] Insufficient Solder Fillet in a PTH

Dear Technetters,

My company has been conducting studies on implementing the use of robotic
soldering in our assembly process.

Whilst experimenting with such equipment, we found our product from our PCB
source to have problems; namely insufficient wetting in the PTH or
(insufficient solder fillet in the PTH).

As we have never seen this problem before, we are no evaluating the root
cause to rule out whether or not it is equipment related.

Your advise on the following matters would be truly appreciated:

a.  What causes insufficient wetting/solder fillet in a PTH?
b.  What are the corrective actions for insufficient wetting/solder fillet
in
a PTH?
c.  Would preheating the PCB's eliminate this problem?
d.  Does the selection of flux have an influence on proper wetting/solder
fillet of a PTH?
e.  Does the size of a hole influence whether or not proper wetting/solder
fillet in a PTH is achieved?

Any and all responses would be truly appreciated.

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