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solder paste(SnPbAg)

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#72513

solder paste(SnPbAg) | 2 August, 2014

Will there be any issue if soder paste of SnPbAg is used for airborne application (PCB)

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#72521

solder paste(SnPbAg) | 4 August, 2014

Whether or not SnPbAg will cause issues is trivial.

You must build to the solder specified on the print.

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#72522

solder paste(SnPbAg) | 4 August, 2014

What do you mean by "airborne"?

We have been using SnPbAg for 15+ years to build assemblies to IPC class II standards although with most assemblies going to Pb free, we are not using it near as much as we used to.

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#72525

solder paste(SnPbAg) | 4 August, 2014

Let me thank you for the reply. We are manufacturing products which are fitted on the aircraft. We are using SN63Pb37 solder paste for PCB assembly. Of late one of the solder paste supplier recommended SnPbAg for better solder-ability & reliability. In view of this we wanted to confirm the reliability issue of the solder joint formed using the combination SnPbAg from an expert/user before taking up for the evaluation process at our end. Also we would like to know the drawbacks associated with the said solder paste ie, with silver combination. Requested to reply

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#72526

solder paste(SnPbAg) | 4 August, 2014

Let me thank you for the reply. We are manufacturing products which are fitted on the aircraft. We are using SN63Pb37 solder paste for PCB assembly. Of late one of the solder paste supplier recommended SnPbAg for better solder-ability & reliability. In view of this we wanted to confirm the reliability issue of the solder joint formed using the combination SnPbAg from an expert/user before taking up for the evaluation process at our end. Also we would like to know the drawbacks associated with the said solder paste ie, with silver combination. Requested to reply

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#72535

solder paste(SnPbAg) | 6 August, 2014

Sn62Pb36Ag2 has a higher liquidus point of 189C as compared to Sn63Pb37 at 183C. You may need to slightly adjust your oven profiles to use it compared to SnPb. We have had good solder-ability and reliability with it in our IPC Class II products. Aircraft components are usually build to IPC Class III which is a higher reliability standard. I can not speak to the use of SnPbAg for Class III products.

Also, we are using water soluble flux with the SnPbAg solder and then washing the boards. The water soluble flux is likely helping us get good solder-ability / wetting.

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#72539

solder paste(SnPbAg) | 7 August, 2014

One of the things you need to know are the parts you are building Flight Critical. Meaning if the board fails will it bring down the aircraft. Or non critical meaning one of the over head light will fail as an example this determines how much latitude you have in making a change.

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#72544

solder paste(SnPbAg) | 7 August, 2014

Sir

The board is flight critical

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#72545

solder paste(SnPbAg) | 7 August, 2014

Sir I more information i did not shared with you. The finish of this critical board is ENIG. Do you recommend ENIG finish for the flight critical boards

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#72567

solder paste(SnPbAg) | 13 August, 2014

This is the perfect combination for the Mission Critical PCBs you require. All of our Airborne Customer Prefer a Leaded Solder to a Lead Free, and often require it. ENIG PCB construction is the strongest method of producing Mission Critical Systems. You Have Done Very Well!! Regards, Anvil

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#72569

solder paste(SnPbAg) | 13 August, 2014

Thank you

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