A 0.8 mm aluminum fin is a spring. Cut it with a full-depth pass and it deflects away from the cutter, the thickness tapers top to bottom, and the fin roots tear. The part still measures 22 fins and the right pitch, so the problem only shows up as a thermal result that is worse than the simulation.

These fins are machined in stepped depth passes with a small-diameter end mill, alternating around the part so the wall never heats on one side. The fin roots get a fillet radius instead of a sharp corner, which is where most of the cooling area actually lives, and every fin is checked for thickness at the root and the tip.

• Stepped fin cutting — 0.8 mm thickness held ±0.03 mm at root and tip.
• Root fillets — R0.4 at the fin base, where the heat actually leaves the wall.
• Alternating passes — keeps the can round instead of oval after 22 fins are cut.
• Flat register face — 0.01 mm, so thermal paste and stator contact are predictable.

1. Thermal review — fin count, pitch, height and wall thickness checked against your thermal model and motor duty cycle.
2. Material verification — 7075-T5 received by heat number with ultrasonic check and 3.1 material certificate.
3. Rough turning — OD and bore roughed with 0.8 mm allowance, the fin band left as a solid ring.
4. First stress relief — low-temperature relief before the fins are cut, so the can does not close in.
5. Bore semi-finish — stator bore semi-finished and stress checked before the wall is weakened by finning.
6. Fin machining — 22 fins cut in stepped depth passes with alternating indexing, root fillets cut in the same program.
7. Second stress relief — a short cycle after finning, then the bore is finished to H7.
8. Anodizing — black anodizing 15-20 µm, bore and register face masked.
9. Verification — fin thickness at root and tip, pitch, base flatness and bore cylindricity on CMM, FAI shipped.

• Fin geometry — straight, tapered, or pin-fin array inside a ducted shroud.
• Wall — 2.5 to 4.0 mm, traded against stator interference and weight.
• Interfaces — O-ring land, threaded boss, or clamped flange at either end.
• Finish — black anodizing for emissivity, hard anodizing for abrasion, or chromate conversion.
• Sampling — 1 pc for a bench thermal run before the batch is released.

Motor geometry, stator stack and winding data are competitive information, so access is limited from the drawing stage onward.

• NDA first — mutual NDA and non-circumvention signed before any file is exchanged.
• Isolated area — dedicated machines and authorized staff, no phones or photography inside.
• Codified routing — internal codes on travelers and labels instead of your part numbers.
• Data control — per-project folders on a permission server, destroyed on request with a record.
• No display — no drawings, part photos or logos in samples, catalogs, the website or social media.

Dongguan Changxinda Precision Technology Co., Ltd. — founded in 2008, 90-102 staff, ISO 9001:2015 certified, annual sales USD 10-20 million, export share 50-60%, serving customers in Europe, North America, Japan and Southeast Asia.

Machining, stress relief, anodizing and metrology run in one plant: 5-axis and 4-axis machining centers, turn-mill centers, surface grinders, wire EDM, CMM, 2.5D vision metrology and automated anodizing lines. About 12,000 aluminum parts ship each month, most of them small precision parts where the fixture and the boring sequence decide the result.

1. 01 Consumer Electronics — Phone, tablet and laptop housings · heat sinks · camera brackets · VR/AR headset structural parts · smart wearable housings
2. 02 Automation & Industrial Equipment — Automation jigs · fixtures · module frames · transmission sliders · motor mounts · sensor housings · conveyor line components
3. 03 Semiconductor & Vacuum Equipment — Vacuum chambers · vacuum fittings · semiconductor equipment precision bases · thermal insulation parts · inspection fixtures
4. 04 Medical Devices — Surgical instrument bases · medical device housings · endoscope components · aesthetic equipment structural parts (medical grade aluminum / stainless steel)
5. 05 Automotive — EV motor housings · battery end plates · sensor brackets · lamp structural parts · aftermarket parts · hydraulic valve blocks
6. 06 Aerospace & UAV — Aircraft structural parts · UAV frames · landing gear components · avionics instrument housings (lightweight precision parts)
7. 07 Optics & Photonics — Optical lens barrels · lens mounts · light source heat sinks · camera module brackets · inspection optical stages
8. 08 Telecommunications — 5G heat sink cavities · filter housings · signal adapter brackets · telecom equipment enclosures
9. 09 Robotics — Robotic arm joint parts · robot bases · reducer housings · AGV chassis structural parts
10. 10 Instruments & Meters — Inspection equipment housings · precision gauge bases · flow meter parts · laboratory equipment components

Two shifts 07:30-22:00, six days a week, with weekend shifts in peak season. Capacity is locked weekly for volume programs, so a rush order never displaces a scheduled batch.

• Samples — 7-10 days, checked on your stator or bearing set before the batch is released.
• Batch — 15-20 days from deposit and drawing approval.
• Buffer stock — semi-finished stock for repeat models, cutting repeat lead time by about 30%.
• Shipping — DHL/FedEx/UPS in 3-5 days for samples; air or sea for volume; EXW Dongguan, FOB Shenzhen or CIF.
• Documents — FAI, 3.1 material certificate, CMM report and packing list with every shipment.

Send STEP / IGES / DWG / PDF and receive DFM feedback plus a formal quotation within 24 hours.

Dongguan Changxinda Precision Technology Co., Ltd. · ISO 9001:2015 · Dongguan, Guangdong, China