Case Study Series

Utilizing Tools for Process Characterization.
–Zach Papiez

Q: How does Rework introduce more potential failures into the process?

A: Because of the variable nature of how rework might be accomplished by an operator, it leaves a lot of room for human error or inconsistency. There will be much less transparency in the exact method used. The operator might also inadvertently damage the protective oxygen barrier formed on the no-clean SMT pastes.

Q: What are acceptable limits for Ion chromatography?

A: The exact acceptable limit for assemblies is not set by the IPC or similar organizations, but generally accepted limits for particular solder types (in this case, no clean) are used for most labs.

Q: How does SIR provide objective evidence?

A: For one thing, SIR can quantify the resistance on a board. This is of greatest value when a dramatic and quick change in this resistance is observed over time which would be a strong indication of something wrong with your process.