Larry,

I'm not sure I agree with your statements.  My two statements which I've been saying for over 40 years are:

1. "Nothing Solders Better Than Solder" and
2. "Nothing Tests Soldering Better than Soldering"

I really don't says these to be funny because for all my experience I haven't run into a situation that disproved either.

The higher melting point of the Pb-Free HASL surface finish shouldn't make it more difficult to solder to the pads.  If the Pb-Free HASL has a SAC composition than the 1-4% silver in the Pb-Free HASL would be a major contributor to contaminating the solder pot.  However, if the Pb-free HASL composition was SN100C I didn't think it would be a major contamination contributor.

My suggestion to Juliano would be to "try it".  If it gives good looking solder joints he might want to do some fundamental evaluations to know they solder joints are "good" but there has been many studies over the years showing that there isn't a reliability issue with mixed alloy solder joints.

Regards,
George
George M. Wenger
Senior Principal Reliability / FMA Engineer
Andrew Corporation - Wireless Network Solutions
40 Technology Drive, Warren, NJ 07059
(908) 546-4531 Office (732) 309-8964 Mobile
E-mail: [log in to unmask]

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Larry Dzaugis
Sent: Thursday, May 17, 2012 8:55 PM
To: [log in to unmask]
Subject: Re: [TN] PCB Lead Free with Tin Lead Process

This is not a good thing to do.
I do not know what you make or how many.

1. It will be more difficult to solder to the pads with the higher melting point HASL 2. The HASL will get in the solder pot. It could conatamiante the pot quickly depending on the material in the HASL. Solder pots are expensive to sell as dross.
3. What data do you have on reliability for the solder joint? The lead free section is thick from the HASL, not the joint that has been looked at. It is not a common process.

On 5/17/12, Juliano Ribeiro <[log in to unmask]> wrote:
> We using glue dot and we'll solder in the Wave Solder Machine.
> We trying solder the pad of the component.
>
> Thank you a lot
>
> Juliano Ribeiro
> Coordenador de Produção - Placas Eletrônicas Elo Sistemas Eletrônicos 
> S.A.
> Fone: (51) 2131 2217    Fax: (51) 2131 2200
> Cel: (51) 9356
> 2844
>
>
>
> -----Mensagem original-----
> De: Larry Dzaugis [mailto:[log in to unmask]] Enviada em: 
> quinta-feira, 17 de maio de 2012 15:12
> Para: TechNet E-Mail Forum; Juliano Ribeiro
> Assunto: Re: [TN] PCB Lead Free with Tin Lead Process
>
> What is the lead free HASL alloy?
> Is it through hole soldering or glue dot SMT?
> Are you trying to solder test pads?
>
> On 5/17/12, Juliano Ribeiro <[log in to unmask]> wrote:
>> Hi to all,
>>
>> Is it possible we use PCB with finishing HASL (Lead Free) in our Tin 
>> Lead Process - Solder Wave?
>> We need modify some parameters how the temperature?		
>>
>> Thank you a lote
>>
>>
>> Juliano Ribeiro
>> Coordenador de Produção - Placas Eletrônicas Elo Sistemas Eletrônicos 
>> S.A.
>> Fone: (51) 2131 2217    Fax: (51) 2131 2200
>> Cel: (51) 9356
>> 2844
>> http://www.elonet.com.br
>>  "Antes de imprimir pense na sua responsabilidade com o meio ambiente."
>>   Adote os 4 R´s (Reduzir, Reutilizar, Repensar e Reciclar)!
>>
>>
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