RM 194: Why Post-Reflow Cleaning Is Becoming Mainstream Again, Part 2

This is part two of a two-part series.

In Part One, we explored how the electronics industry transitioned from a clean-everything approach to one where cleaning became optional. But what happens when the assumptions behind “no-clean” collide with modern electronics design?

In this episode of Reliability Matters, Mike Konrad examines how the definition of cleanliness has fundamentally changed.

As assemblies became smaller, denser, and increasingly deployed into harsh environments, the industry discovered that historical cleanliness standards were no longer sufficient to predict real-world reliability. Modern low stand-off components like QFNs, BGAs, and CSPs create tight geometries where residues can become trapped and difficult to remove, while thermal cycling and internal condensation can create localized harsh environments inside the product itself.

This episode explores:
• Why IPC moved away from fixed cleanliness limits
• The growing importance of SIR and ROSE testing
• Why “cleanliness” is now tied to risk, not a number
• How internal condensation can trigger electrochemical migration
• Why no-clean flux has become the most commonly cleaned flux type in the industry
• The return of cleaning as a mainstream reliability process
• Why modern assemblies require aggressive spray-in-air cleaning technologies instead of historical immersion-based vapor degreasing methods
• How diffused spray patterns improve cleaning beneath low stand-off components

Konrad also explains how modern cleaning challenges are no longer just about chemistry. They are about physics, fluid delivery, and whether the cleaning process can physically reach contamination hidden beneath today’s densely packed components.

As electronics continue to shrink and reliability expectations continue to rise, one question becomes increasingly important: Clean enough for what?

If you work in electronics manufacturing, reliability engineering, process engineering, or quality assurance, this episode provides a detailed look at why post-reflow cleaning has once again become a critical part of modern electronics manufacturing.