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Vapor phase soldering is a specific form of SMD reflow soldering where the solder connection is made in a controlled vapor phase. Unlike convection reflow soldering, it involves soldering in hot vapor instead of hot air. Perfluorinated polyether (PFPE) is used to generate the vapor. The liquid and vapor are electrically non-conductive. PFPE fluids come with various boiling points, allowing the soldering temperature to be defined through the medium based on the application.

For lead-free soldering, GALDEN LS-230 is typically used, which means soldering at a maximum of 230°C. Since PFPE is chemically inert, the vapor displaces oxygen, enabling soldering in an oxygen-free atmosphere. There are no residues of the fluid on the soldered boards.

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The advantages of vapor phase soldering in SMT soldering are:

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1. Uniform and reliable solder connections: The use of vapor as a heat transfer medium achieves even temperature distribution without heat shadows, resulting in high-quality and reliable solder connections. This minimizes the risk of cold solder joints or inadequate connections.

2. High reproducibility: As the soldering process takes place in a controlled environment, reproducibility in vapor phase soldering is very high.

3. Protection against oxidation: The vapor phase acts as a protective layer, preventing the formation of oxide layers on the components to be soldered. This improves the wetting of component surfaces and the quality of the solder connection.

4. Applicability to complex assemblies: Vapor phase soldering allows effective heat transfer to complex assemblies with multiple components, different package sizes, and shapes. This enables the soldering of challenging joints.

5. Gentle soldering: PFPE fluid with a boiling point of 230°C is used for lead-free soldering. Therefore, the components and the board are soldered gently, reaching a maximum of 230°C in the peak region.

6. Safe soldering: Since relatively low temperatures are required for soldering, and the maximum temperature is defined by the boiling point of the Galden fluid, overheating cannot occur with proper application.

7. Energy-efficient: Compared to other soldering methods, vapor phase soldering is energy-efficient due to lower temperatures and efficient heat transfer.