Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


What to use SAC305 or SAC405??

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Haris

#49045

What to use SAC305 or SAC405?? | 14 April, 2007

Hi all, Although i know that increase in the percentage of Ag will increase the cost but i didnt find any standard or rule from that i know what type eutectic alloy is helpful for what type of components? and for changing the % of the compositon of alloy does have the effect on the oven also ?

Thanks Muhammad Haris.

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#49060

What to use SAC305 or SAC405?? | 16 April, 2007

I believe SAC305 will result in a lesser amount of Ag3Sn inter-metallic compounds being formed along the joint boundary and in the sphere. Studies have been shown to point out a significant difference between the number and size of Ag3Sn plates in SAC305 / SAC405 joints. A higher number of Ag3Sn plates means, a larger-than-planned % of pure Sn being available for joint formation, which while being good in a way, also results in thicker (may I remind, brittle) joint boundaries of Cu3Sn and Cu6Sn5.

The smaller the sphere, the more effect this could have on the overall joint reliability. SAC305 would be a better option, if you would ask me.

Comments, anyone...

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PFI

#49071

What to use SAC305 or SAC405?? | 17 April, 2007

take a look at sn100c, less dross & better wetting than sn/pb alloys.

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Jane

#49073

What to use SAC305 or SAC405?? | 17 April, 2007

There are several alloys had been using in the industry. For SMT: most people use SAC305 For Wave: most of them use SAC305,SC100C,SCS7,and SACX0307. Of course, different alloy composition have its own recommended profile. There is no such rule telling us which alloy is suitable to what type of components. As long as the solder joint according to IPC standard, and as long as the product pass the reliability test, the solder alloy is consider a good alloy "so far".

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Wayne

#49076

What to use SAC305 or SAC405?? | 17 April, 2007

Yes, all the leadfree solders are currently for consumer products. Military and aerospace industry haven't implemented leadfree yet. They are still study which to go! Maybe that time, we all can follow military std and having high reliability products. Right!

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