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High Melting Point Solder with alloy composition of 93.5 Pb 5 Sn 1.5 Ag

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#72608

High Melting Point Solder with alloy composition of 93.5 Pb 5 Sn 1.5 Ag | 25 August, 2014

We are in the process of qualifying our SMT lines for the High Melting Point Solder with alloy composition of 93.5 Pb 5 Sn 1.5 Ag.If any one has already an experience with this alloy,kindly do give ur inputs on the process of profiling . The reflow details are BTU PYRAMAX150N (10 Zone Heating and 2 Zone Cooling).

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JAX

#72609

High Melting Point Solder with alloy composition of 93.5 Pb 5 Sn 1.5 Ag | 25 August, 2014

With a melting point of roughly 300°C, you would need to have the product see temperatures peaking around 325°C at a minimum. (I would make sure the components and PCB materials can withstand these temperatures) Most convection ovens do not go over 350°C zone temperatures and would require a very slow belt speed to accomplish the product heating. (I would check paste chemistry to ensure this extended time does not burn off the flux) I am unaware of anyone that uses convection reflow for HMP soldering, it is normally a Hand and/or Wave solder operation... with limited acceptance using laser.

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#72613

High Melting Point Solder with alloy composition of 93.5 Pb 5 Sn 1.5 Ag | 25 August, 2014

Numerous people use the Pyramax oven to process high temp solder but your success will depend upon the mass of your board.

To maximize the probability of success you should use the highest convection rate (IWC) possible to enhance heat transfer and use a nitrogen atmosphere to expand the process window. By using high convection rates you increase the impingement velocity of the gas and thus the heat transfer efficiency in a convection oven. The use of a nitrogen slows the oxidation of the joints thus extends the time flux works.

A few additional comments: 1. Be sure that the thermal barrier that you use on your profiler will protect it for the time and temperature you will be running. 2. I suggest that you use TCs with fiberglass insulation which is good to 482 C instead of Kapton which is limited to 316 C. 3. Some Pyramax ovens have a 400 C option but it is safe to assume that yours is the standard 350C – In some cases it is possible to upgrade an oven to 400C or by talking with the factory be able to run at 360C without making any physical changes.

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