Axial fan impeller blades that start as a C355.0 casting and finish on a 5-axis machine. One job covers vacuum melting, X-ray levels, T-6 temper, reshaping and shank tolerances.
Most blade problems are decided before the first cut.
A blade cast straight, quenched, then tempered often comes back with twist outside the drawing. The airfoil angle is wrong, the fan runs out of balance, and the whole set has to be reworked or scrapped. Reshaping has to be planned into the route, not added after the fact.
Shrinkage and gas porosity tend to collect near the shank, exactly where bending stress is highest. If the casting is only checked in easy areas, the defect ships and shows up as a crack in service. Film and X-ray levels have to be written per zone.
Machining past the as-cast skin exposes subsurface porosity that looked acceptable on the outside. The part is now out of print on wall thickness and cannot be welded back to drawing without re-heat-treat.
If the shank datum is cut before reshaping, the bend moves the seating face and the blade no longer sits flat in the hub. Shank machining and reshaping have to be sequenced, not run as two independent operations.
One route from melt to finished blade, held on the same drawing.
For this new application impeller, the customer selected C355.0 for its strength at elevated temperatures. It is an Al-Si-Cu alloy with a fine structure after T-6, and it can be sand cast or permanent mold cast. Sand casting suits larger, lower-volume blades; permanent mold suits smaller sections and higher strength demand.
Melting runs in a high vacuum melting casting furnace with high tilt automatic equipment, which limits gas pickup before the pour. We agree the X-ray acceptance zones with you before the first heat. Typically Level 2 near the shank and Level 4 elsewhere, tested to ASTM E155.
Blades are heat treated to T-6, which means solution treatment, quench, then artificial aging. Quenching is where twist moves. We measure the part after quench, then add a reshaping operation in a dedicated fixture that bends the blade back to the airfoil tolerance before tempering.
Base machining runs early enough that the twist characteristics stay intact, and final shank work comes after reshaping so the seating face is true. That order matters more than any single tolerance on the drawing.
Use this to decide before you spend on tooling.
| Condition | Cast and machine | Machined from solid |
|---|---|---|
| Blade size | Medium to large axial fan blades | Small blades and thin sections under 3 mm |
| Quantity | Low to medium, one-off to a few hundred | One prototype up to 10,000+ parts |
| Airfoil shape | Complex twist that is hard to mill in one setup | Simple or moderate airfoil |
| Material | C355.0 or similar castable alloy | 6061, 7075, 17-4PH, Ti-6Al-4V |
| Inspection need | X-ray and film per ASTM E155 | Dimensional and surface only |
| Cost driver | Pattern and heat treat | Bar stock and cycle time |
Different blades need different steps. Pick what your drawing calls for.
Investment and vacuum casting for impeller blades and similar airfoil parts where gas content has to stay low. C355.0 and other castable alloys.
16 simultaneous 5-axis centers handle the twisted surfaces and the shank in fewer setups, which keeps the airfoil and the mounting face in one coordinate system.
Shank diameters, hub bores and mounting faces turned and milled to ±0.005 mm where the drawing needs it.
T-6 temper with reshaping in a dedicated fixture between quench and tempering, so twist stays inside tolerance.
Polished finishes for engineered components, plus bead blasting, brushing and anodizing when the blade runs in a wet or abrasive environment.
A machined or printed blade first, so you can check fit in the hub and airflow before committing to a pattern.
Numbers we can commit to on a cast blade route.
| Item | Capability | Notes |
|---|---|---|
| Casting alloy | C355.0 | Sand or permanent mold, customer selected |
| X-ray | ASTM E155 | Level 2 near shank, Level 4 elsewhere |
| Heat treat | T-6 | Reshaping before tempering |
| Machining tolerance | ±0.005 mm | ±0.0002 in where specified |
| Surface finish | Ra 0.8–1.6 μm | Polished on request |
| Max part size | 4,000 mm | Largest machine travel |
| Inspection | 100% before shipment | Reports on request |
| Lead time | Quote in 12 hours | Parts ship in 3–5 days |
Founded in 2011. Three wholly-owned plants and 150 technicians across Dongguan and Singapore.
16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers.
Quotation and free DFM analysis within 12 hours of receiving your drawing and 3D file.
Production can start within 24 hours once the route and fixture are approved.
Raw material check, in-process monitoring and final inspection before every shipment.
From one prototype blade to 10,000+ part runs, on the same drawing and process.
Blades for axial fans run in dust and abrasive air, so the airfoil surface and the shank fit both have to hold.
Elevated-temperature service is why C355.0 was chosen. Hot strength has to survive the full duty cycle.
Blade sets have to match each other. Twist tolerance repeats across the set, not just on one part.
One machined blade for fit check, then the cast route once the airfoil is signed off.
Cast-and-machine makes sense when the airfoil is complex, the blade is large, and the quantity is low to medium. Milling a deep twisted airfoil from bar stock removes a lot of material and cost.
Machining from solid is still the better call for small blades, thin sections under about 3 mm, or when you need 10,000+ identical parts with no casting variation.
ASTM E155 sets acceptance levels by severity. Level 2 near the shank allows less porosity in the high-stress zone, and Level 4 in the rest of the blade allows more.
We agree those zones with you before the first heat, because the shank carries the bending load and the blade body mostly carries airflow.
Quenching is where twist moves the most. After quench, we measure the blade, then bend it in a dedicated fixture to bring the airfoil back to tolerance. Tempering runs after reshaping.
Base machining is sequenced so the twist characteristics stay intact, and final shank machining follows reshaping so the seating face stays flat.
±0.005 mm (±0.0002 in) where the drawing specifies it. The shank is the locating feature, so it gets the tightest control and the most inspection attention.
The airfoil surface is held to the profile tolerance on your drawing, which is usually looser than the shank by design.
Yes. There is no minimum order quantity, and we can machine or print a single blade first so you can check fit in the hub and check airflow before pattern work starts.
Once the airfoil is signed off, the same drawing moves to the cast route with reshaping and T-6 temper added.
Polished finishes are common on engineered blades because surface roughness affects airflow and fouling. We work in the Ra 0.8–1.6 μm band on machined surfaces.
For wet or abrasive environments, anodizing or a coating may be specified on top. Tell us the service environment and we will say which finish fits.
A 2D drawing with the X-ray zones marked, a 3D model, the alloy, the quantity and the service temperature. If you have an existing pattern, say so.
Quotation and free DFM analysis come back within 12 hours. Uploads are secure and confidential, and an NDA is available on request.
Uploads stay secure and confidential. We can sign your NDA or provide ours before you send the model.
Access to the files is limited to the engineers and machinists who run the job.
Tell us the alloy, the X-ray zones and the service temperature. You get a quote and a DFM read within 12 hours.
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Upload your 3D model or 2D drawing and get a quotation with a free DFM analysis. Maximum processing size 4,000 mm.
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