MANASSAS, VA – Heraeus and Zestron recently completed an evaluation of 10 solder pastes to characterize the ability to clean flux residues on reflowed assemblies. The effort also examined each paste in its unreflowed state to identify the best methods of removal from stencils and misprinted boards.

The companies have released application bulletins for cleaning the paste formulations. 

The pastes, which include various no-clean and water-clean formulations, were cleaned using inline, batch and ultrasonic processes.

The application notes contain recommended operating parameters for inline, batch, ultrasonic, stencil and misprint cleaning. They also include suggested concentrations, temperatures, timing and rinse information as applicable for each process. The bulletins may be obtained by contacting Dawn Lehman at Heraeus (dawn.lehman@heraeus.com) or Sabine Braun at Zestron (s.braun@zestronusa.com).