Rust on ModalAI ESC Component? Do I need to be concerned?

[Jaroslav Richters]

Found a rusty component on one of ModalAI ESCs. Does this effect performance or reliability? Should I be concerned? Is this eligible for return? @Vinny

[Vinny]

@Jaroslav-Richters
Yes, we are aware there is a component on our ESC assemblies and other circuit card assemblies (CCAs), specifically, the Vishay IHLP series inductor, that is at risk of visible oxidation.

We’ve looked into it closely and want to provide a clear update for everyone:

Performance: Vishay, the inductor manufacturer, has confirmed in a published white paper that this oxidation does not affect electrical performance or reliability. There is no need for concern or an RMA, functionality is not impacted. If desired, you may clean any visible rust using your preferred cleaning agent suitable for your production or maintenance process. For full details, you can review their white paper here:
Vishay IHLP Oxidation White Paper (PDF):

Root Cause: The visible oxidation is most likely related to our use of a water-soluble flux during assembly, which requires steam cleaning to remove residue. However, given Vishay’s acknowledgment of the issue, there may be other factors at play and not just our processing steps.

Mitigation: We have already begun including desiccant in all ESD shield bags for ESC assemblies and any other CCAs with the IHLP inductor. If further action is needed, we are prepared to implement additional measures, such as extended baking of the boards after cleaning or applying protective coatings to the inductors.

Commitment: You can expect improvement in upcoming shipments. We take cosmetic quality seriously and will continue to monitor and enhance our process as needed.

We appreciate all customer feedback; clear communication about issues like this help us get better. Thanks for helping us raise the bar.