MCN #001 — Reliability Improvement (Impeller Materials)

Manufacturing Change Notice (MCN #001)Product: Wright Fan 120 mmSubsystem: Inlet & Outlet ImpellersCategory: ReliabilityStatus: In ProductionEffective Date: August 2025

Summary

Wright One has implemented a material update to both the inlet and outlet impellers used in the 120 mm Wright Fan to improve dimensional stability and long-term reliability under sustained high-temperature, high-humidity operating conditions.

This change was informed by aggregated field data, validated through environmental stress testing, and is now fully incorporated into production.

Field Observation

Across a limited number of deployments operating under sustained thermal load, Wright One observed vibration-related behavior initially reported as rotor imbalance.

Further analysis showed the behavior was isolated to impeller geometry, not the motor or electrical system, and occurred in environments combining:

• elevated exhaust temperatures, and
• high ambient humidity.

The behavior was most pronounced on the outlet (exhaust) impeller, which is directly exposed to heated ASIC airflow, but material response characteristics were evaluated across both airflow sides of the system.

This pattern was observed across multiple independent sites operating under similar environmental conditions.

Root Cause Analysis

Teardown and inspection confirmed the behavior was not caused by motor imbalance, bearing failure, or electrical fault.

The root cause was identified as:

• material expansion and moisture absorption under combined heat and humidity exposure,
• resulting in reduced clearance margins between the impeller and fan frame,
• leading to intermittent mechanical interaction during operation.

While the failure mode manifested on the exhaust side, Wright One determined that material margin improvements were warranted across both inlet and outlet impellers to maintain symmetric reliability under worst-case environmental conditions.

Manufacturing Change Implemented

Wright One implemented the following corrective actions across both inlet and outlet impellers:

• Updated impeller material specification with improved dimensional stability
• Material hardening to reduce thermal and humidity-driven expansion
• Environmental stress testing conducted at 100°F and 100% relative humidity
• Clearance validation performed under sustained heated operating conditions

All updated impellers successfully completed validation testing without clearance interference, vibration, or imbalance behavior.

These changes are now active in production.

Reliability Impact

The updated impeller materials maintain geometric stability across elevated temperature and humidity ranges typical of ASIC operating environments.

By applying the update symmetrically to both inlet and outlet impellers, Wright One improves long-term clearance margins, reduces vibration risk, and increases mechanical reliability under sustained duty cycles.

Applicability

• New units:All 120 mm Wright Fans produced after the effective date include the updated inlet and outlet impeller materials.
• Previously deployed units:Existing units remain fully covered under Wright One’s subscription-based replacement program.

No customer action is required.

Customer Impact

Wright One’s subscription model is designed to absorb reliability variability on behalf of the customer.

If impeller-related degradation occurs in the field, Wright One will manage replacement through the existing service program in accordance with subscription terms.

Customers are not required to diagnose, retrofit, or stock spare components.

Notes

This Manufacturing Change Notice follows Wright One’s Reliability & Manufacturing Transparency Charter and documents a completed, production-released manufacturing update.

Future Manufacturing Change Notices will follow the same publication standard.