An enterprise AI inference server used an eight-fan tray as a removable cooling module. The fabricated structure had to locate the fans, align them with the internal duct partitions and slide into the chassis without binding.
The project addressed these mechanical relationships together. Its scope was the tray, attachment features, partitions and assembly checks for the configured module, rather than a general claim about server cooling performance.
The customer’s challenge
Accumulated error across the fan mounting-hole patterns led to vibration and abnormal noise after installation. Fan centers did not align consistently with the duct openings. At the same time, the tray’s rail interfaces made insertion and removal difficult in the chassis.
A tray that passed an isolated dimensional check could still perform poorly when fitted with all eight fans and installed in the server. The customer needed acceptance checks that reflected that assembled condition.
Material and fabrication route
The tray used 1.2 mm SECC electrogalvanized steel, with 1.0 mm galvanized steel for the duct partitions. The module fitted a 19-inch, 3U chassis.
Process route: Laser cutting and CNC punching of the fan hole patterns → bending → hardware insertion → welding → powder coating → fan preassembly → vibration testing → duct-alignment inspection → packing.
The revised hole-pattern operation used a common CNC punching setup rather than allowing the relationships between fan positions to accumulate independently.
Manufacturing changes
The fan mounting patterns were produced together with a recorded position tolerance of ≤0.1 mm. The rail-contact features were corrected after bending so that the finished tray could travel through the chassis interface without binding.
Vibration-isolating pads were added at the fan installations. A dedicated alignment fixture checked the relationship between the installed fans and the duct openings. Every preassembled tray received that inspection.
These changes connected three acceptance points: mounting-hole geometry, the assembled fan-to-duct relationship and the completed tray’s fit in the chassis. None was used as a substitute for the others.
Engineering analysis
The mounting holes establish where the fans sit, but the useful final relationship is between the fans, partitions and chassis. This explains why the project retained an assembled alignment check after improving the hole-pattern process.
Rail fit also matters beyond convenience. A removable module has to reach its intended installed position consistently before its other interfaces can be evaluated. Correcting the rail-contact features therefore supported both assembly and servicing.
The sound-level results below are project-reported measurements. The supplied record does not specify measurement distance or frequency weighting, so the values should not be used as a standardized comparison with another server.
Inspection and project results
| Project measurement or production detail | Recorded value |
|---|---|
| Fan mounting positions | 8 per tray |
| Mounting-hole pattern position | ≤0.1 mm |
| Fan-to-duct alignment offset | ≤0.5 mm |
| Recorded sound level | ≤55 dB |
| Recorded sound-level reduction | 8 dB |
| Tray insertion/removal force | ≤30 N |
| Chassis interface | 19-inch, 3U |
| Assembly acceptance | ≥99% |
| Project production quantity | 60 trays per week |
The project recorded smooth insertion without jamming, reduced vibration noise and airflow meeting the customer’s requirement. No airflow quantity or temperature reduction was supplied, so no additional thermal-performance number is attributed to the tray.
Planning a similar OEM component
For an AI equipment rackmount chassis or related fan shrouds and guards, provide:
- Fan drawings, installed orientation and attachment requirements.
- The duct and partition geometry relative to the fan centers.
- Chassis-rail interfaces and the required service-removal path.
- The assembled inspection condition and any specified acoustic or vibration test method.
Separating these mechanical inputs from the OEM’s complete thermal design makes the fabrication and inspection scope easier to agree.
