Sunil,
Also check your solder for metallic impurities.  Some favour the formation
of icicles.

Bev Christian
Nortel Networks

> -----Original Message-----
> From: Feng Yi,BISC PD IE(BJ) [SMTP:[log in to unmask]]
> Sent: Wednesday, May 05, 1999 4:38 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] Icicle formation on wave soldering
> 
> Dear Sunil, 
> the same problem has been found in our company, and we solved it though
> below mentioned methods. 
> 
> 1) increase pre-heat tempreture to 160¡æ 
> 2)increase the spraying flux 
> 3)only use single wave solder, not double wave solder 
> 
> 
> Best Regards 
> 
> 
> Qu Zenglong 
> 
> Industrial Engineering Department 
> Production Division 
> BISC, China 
> Tel: 0086-10-64346323 
> Fax:0086-10-64367731 
> e-mail: [log in to unmask] 
> 
>       ---------- 
> From:   Sunil Gupta[SMTP:[log in to unmask]] 
> Reply To:       TechNet E-Mail Forum.;[log in to unmask] 
> Sent:   Wednesday, May 05, 1999 11:49 AM 
> To:     [log in to unmask] 
> Subject:        [TN] Icicle formation on wave soldering 
> 
>       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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