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Wang Chao is the technology manager at UK-based ITRI Ltd—a not-for-profit membership-based industry organization dedicated to supporting the tin industry and expanding tin use. He is also the secretary of the ITRI-IPC China Solder Technology Group (CSTG), a membership group that aims to lead cooperative projects and to provide solutions to drive the next generation of solder technology development.
In an interview with SMT Magazine, he discusses the biggest challenges in solder paste printing, how the solder paste material impacts the process, and the future for soldering and paste printing.
Stephen Las Marias: What are the biggest challenges in solder paste printing?
Wang Chao: I think the biggest challenges in solder paste printing is how to get the good solder joint amid continuous miniaturization trend. For instance, in consumer electronics, the challenge is that the boards are becoming smaller, and tolerances are become tighter and tighter. Tin whiskers is a big issue, so does solder cracking side effects. I think these are among the biggest problems in the solder industry worldwide for the moment.
Las Marias: How does the solder paste material impact the process?
Wang: Different kinds of solder components have different melting points, so the melting profile will be different. Paste residue also affects the cleaning process, as some pastes need cleaning, but some do not.
Las Marias: Aside from miniaturization, what other industry or market trends are affecting the solder paste printing process?
Wang: I think innovative equipment and electronic components will affect paste printing process a lot in the future. For example, the improvement in jet printing equipment could replace paste printing in the future. Also, as 3D printing is in development, the future may see less paste printing needed. Graphene and stanene applications will also impact solder paste printing.
Las Marias: Can you give a list of "best practices" for solder paste printing? What factors do users need to consider when it comes to solder paste printing?
Wang: I think the cost performance is the major factor when it comes to solder paste printing.
Las Marias: What do you think is the future for solder paste printing?
Wang: The printing process should be more accurate and diversified. I also think the paste powder size will become even smaller. Also, low-temperature pastes will be used widely in two to three years. Mixed powder technology will be a good technology for many special applications.
Las Marias: Thank you.
Wang: Thank you.