Flux-coated solder preforms allow you to reduce the amount of flux that’s presented to the joint and increase the solder volume. SMT expert Phil Zarrow interviews Seth Homer to explain the benefits.
Phil Zarrow: So, Seth, what are flux-coated preforms? What are the benefits of using them?
Seth Homer: Flux-coated preforms allow you to reduce the amount of flux that’s presented to the joint and increase the solder volume. Traditionally, with solder paste, you’re 50 percent flux. That excess flux has to go somewhere, and it usually resides on the board, and it has to be cleaned. But it also contributes to voiding under bottom termination components. So, it’s a reliability thing.
Phil Zarrow: What applications benefit most from flux-coated preforms?
Seth Homer: Applications that benefit the most from the use of flux-coated preforms are usually like bottom termination components, where voiding is a concern and reliability is important over the long-term. In addition to that, any component that’s going to see stress, like a USB connector, or something like that, the added solder volume will help.
Phil Zarrow: Indium Corporation has a flux-coating material called LV1000. What are the benefits of this particular material?
Seth Homer: LV1000 is a departure from our normal flux coating offering in that it’s manufactured differentl; it preserves the flatness of the part. But from a formulation standpoint, it helps reduce voiding because it doesn’t produce as many volatiles.
Phil Zarrow: Seth, are there any specific handling requirements with flux-coated preforms?
Seth Homer: No. They can be handled in very much the same way you handle components. Obviously, you need to handle them with the same level of care to preserve flatness and that sort of thing, but, ultimately, no. I would say that they’re very durable, they can handle the average environment of any factory floor, so they’re very easy to handle.
Phil Zarrow: Where can an engineer go for additional support on flux-coated preforms?
Phil Zarrow: Very good. Seth, thank you very, very much.
Seth Homer: You’re very welcome.