Sunil,

We had the same problem but instead on capacitors and resistors the icicles
were formed on fuses.  The problem could be solved by varying different
parameters. 1) we used more flux (sprayfluxer), but to much gave problems
with the ICT test (pintestability); 2) we used a higher pre-heat
temperature (Tmax=126C); 3) we used more nitrogen.  Finally we choosed for
the last one.  At the moment we don't have any problems anymore.

Inge Schildermans
Alcatel Bell


While wave soldering the mixed technology boards I am facing the problem of
icicles being formed on the solder side. The icicles are only on SMDs
(capacitors and resistors, there are no other SMDs)  while not observed on
lead thru components. The machine parameters are:
   Bath temperature: 245 deg C
   Conveyor speed: 1m per minute
   Fluxing thru foam fluxer
   PCB temperature before soldering: 100 deg C
   Preheat zone length: 1.5 m

The problem got solved by heating the boards at 60 deg C and than passing
them thru the fluxing and soldering.

I want to eliminate the Icicle problem and also remove the requirement of
baking.
Can you give me ideas.

regards

Sunil Gupta
Manager Process Engineering
Tata Telecom Ltd.

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