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SAC305 soldering to 58Bi/42Sn

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#60477

SAC305 soldering to 58Bi/42Sn | 19 November, 2009

Hi,

we have an idea of running one side of PCB using 58Bi/42Sn solder to prevent glueing components on other side of PCB when board is on second run through SMT process.

I wonder what issues we can meet once we try to use SAC305 when reworking some SMD components if they are soldered to PCB with BiSn solder alloy ?

Any feedbacks and expieriences in this field would be very appreciated.

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#60499

SAC305 soldering to 58Bi/42Sn | 19 November, 2009

Which components are falling off during the second reflow?

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#60542

SAC305 soldering to 58Bi/42Sn | 24 November, 2009

Actully none couse we glue them. Please see attached file - there are red dots marking glue placment. I understand you want to check if there is any sense in gluing components.

I`ll ask one more time - Is anoyne who reworked SMDs with SAC305 where components were soldered with 58%Bi-42%Sn ?

Is anyone who tried 58Bi42Sn at all ? What are your feedback/experiences with this alloy ?

Attachments:

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#60543

SAC305 soldering to 58Bi/42Sn | 24 November, 2009

I have used SnBi from Alpha, and it worked well. The only issue I found is that you cannot have ANY Pb contamination.

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#60547

SAC305 soldering to 58Bi/42Sn | 24 November, 2009

I think you're okay reworking with SAC305 but rework with SnPb will result in a SnPbBi alloy with a lowered melting point that may pose reliability concerns. As far as suitability of 58Bi42Sn goes - depends on your requirements.

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#60548

SAC305 soldering to 58Bi/42Sn | 24 November, 2009

We put it in one flow soldering machine probably 12 years ago now worked really well but was extremely brittle you maybe better off with the 1% Ag alloy as its more ductile. Look at AIM Solders site if you want further information on the alloy Itis also available in cored wire if your unsure on SAC305 but I cant think of any reason why it should be a problem cheers greg

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#60579

SAC305 soldering to 58Bi/42Sn | 30 November, 2009

"Environment Friendly Electronics: Lead-free Technology", J Hwang, Electrochemical Publications, 2001 [0901150401], Chapter 6.2, contains a significant amount of data on 58Bi/42Sn that may help you better understand the 58Bi/42Sn solder alloy.

We're not so sure that you'll find much on SAC305 soldering to 58Bi/42Sn, because 58Bi/42Sn is uncommon.

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