Manufacturing overview · Typical process
Ø70 mm rotor cup · 24 / 48 V · 60–120 W
The workhorse of EC fans, circulation pumps and appliance drives: the magnets sit inside a rotating steel cup around a fixed stator, giving high torque per volume and a large inertia for smooth low-speed running. Powder-coated 12-slot stator, 14-pole NdFeB rotor, Hall board on the stator base.
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Click a model for full specifications and curves.
| Model | Voltage | Rated power | Rated torque | Rated speed | Current | Rated efficiency | Body length |
|---|---|---|---|---|---|---|---|
| NBL6038 (24 V) | 24 V | 118 W | 0.284 N·m | 3,959 rpm | 5.8 A | 84.6 % | 38 mm |
| NBL6038 (48 V) | 48 V | 123 W | 0.317 N·m | 3,717 rpm | 2.98 A | 86.3 % | 38 mm |
| BL5520O-V3 | 24 V | 16.3 W | 0.0724 N·m | 2,152 rpm | 0.947 A | 71.8 % | 22.5 mm |
12 main assembly steps. Each step lists its key equipment and instruments, their main suppliers, and the technical control points.
Electrical-steel coil is punched in a progressive die (teeth, slots, bore) and interlocked in-die into stator cores; the rotor needs no laminations because the steel cup carries the flux.
Technical control points:
The preheated core is coated with epoxy powder in an electrostatic or fluidised-bed coater and cured; the tooth tips at the outer diameter are masked or brushed clean because they face the air gap.
Technical control points:
A flyer or nozzle winder lays the concentrated coils on the outward teeth, indexing tooth by tooth, and hooks the start and finish wires onto terminal pins in the stator base.
Technical control points:
The wire ends wrapped on the terminal pins are dip- or iron-soldered at a temperature that strips the enamel, and the star point is made.
Technical control points:
Resistance, surge (turn-to-turn), hipot and winding direction are tested before the stator is mounted.
Technical control points:
For humid or vibration-heavy duty the wound stator is trickle-impregnated and cured; many dry-indoor fan stators rely on the powder coating alone.
Technical control points:
The stator is pressed onto the bearing tube of the die-cast base, the Hall PCB is fixed and its pins soldered, and the bearings are pressed into the tube.
Technical control points:
Magnets are bonded to the inner wall of the deep-drawn steel cup with a fixture that sets the pitch, the adhesive is cured, and the shaft is pressed or riveted into the cup hub.
Technical control points:
The magnets are magnetized in the cup with a 14-pole fixture (or pre-magnetized segments are inserted), then the surface field is measured.
Technical control points:
Because the large-diameter cup carries most of the inertia, it is balanced by drilling or adding mass on the cup rim.
Technical control points:
The rotor shaft is inserted through the bearings, axial play is set with washers and a circlip, and the lead cable is fixed to the base.
Technical control points:
Hipot, no-load current and speed, back-EMF, Hall signals, noise and vibration are tested, with sampled load-curve tests on a dynamometer.
Technical control points:
Suppliers are representative examples (international / mainland China), not an exhaustive or endorsed list.
Progressive stamping and in-die interlocking of stator and rotor laminations.
Selection criteria: Tonnage 60–200 t, 200–800 spm, bottom-dead-centre accuracy.
Used in: 1. Stator lamination stamping & interlocking
Equipment page →Forms and interlocks laminations; determines core accuracy and burr.
Selection criteria: Number of stations, regrind interval, stack-height control method.
Used in: 1. Stator lamination stamping & interlocking
Equipment page →Verifies dimensions, geometry and runout.
Selection criteria: Measurement uncertainty, probing system.
Used in: 1. Stator lamination stamping & interlocking
Equipment page →Coats the slots and end faces of small stator cores with an insulating epoxy layer (fluidized bed or electrostatic), replacing slot liners.
Selection criteria: Coating thickness control, masking of the bore and tooth tips, preheat and cure temperature, cycle time.
Used in: 2. Stator powder coating
Equipment page →Winds concentrated coils on the outward-facing teeth of outer-rotor stators (flyer or nozzle type).
Selection criteria: Number of spindles / flyers, wire-diameter range, indexing accuracy, tension control, automatic wire hooking and cutting.
Used in: 3. Outer-stator winding
Equipment page →Solders winding ends to lead wires or a terminal PCB; solderable enamel is stripped by the solder heat.
Selection criteria: Tip temperature stability, solder-wire feed, positioning repeatability, fume extraction.
Used in: 4. Terminal soldering, 7. Stator mounting & Hall board
Equipment page →Winding resistance, turn-to-turn insulation, hipot and insulation resistance.
Selection criteria: Surge voltage, waveform-comparison algorithm, test cycle time.
Used in: 5. Stator in-process test
Equipment page →Impregnates windings with varnish and cures it for insulation, heat transfer and vibration resistance.
Selection criteria: Vacuum level, heating method (current or oven), temperature profile.
Used in: 6. Trickle impregnation (optional)
Equipment page →Rotor-to-shaft and bearing press-fits with force–displacement monitoring.
Selection criteria: Force / displacement resolution, curve evaluation windows.
Used in: 7. Stator mounting & Hall board, 8. Rotor cup assembly, 11. Final assembly
Equipment page →Applies adhesive for bonding rotor magnets.
Selection criteria: Shot-volume accuracy, 1K / 2K adhesive capability.
Used in: 8. Rotor cup assembly
Equipment page →Multi-pole magnetizing of rotor magnets, followed by surface-field measurement.
Selection criteria: Stored energy, peak current, fixture pole count and cooling.
Used in: 9. Magnetizing
Equipment page →Measures and corrects rotor unbalance (material removal or addition).
Selection criteria: Minimum achievable residual unbalance, balance grade (e.g. G2.5 / G6.3).
Used in: 10. Rotor balancing
Equipment page →End-of-line electrical safety tests.
Selection criteria: Output voltage, leakage-current resolution.
Used in: 12. End-of-line test
Equipment page →No-load, load, T–N curve, efficiency, back-EMF and Hall-phase testing.
Selection criteria: Torque range and accuracy, speed range, data acquisition.
Used in: 12. End-of-line test
Equipment page →Main raw materials, purchased components and auxiliary materials. ★ marks items critical to performance or cost. Quantities are typical and vary by model.
| Part | Class | Material | Key specification | Qty | Supply chain / regions | Representative suppliers | Process | Tests |
|---|---|---|---|---|---|---|---|---|
| ★Stator core | Raw material | Non-oriented Electrical Steel | 35W300–50W470, 0.35–0.5 mm | 1 stack | Mills are outside the Pearl River Delta (Baosteel, Shougang, Ansteel); Pearl River Delta buyers get slit coil from mill service centres and steel distributors in Foshan (Lecong) and Dongguan, or buy finished cores from stamping houses. Ask for the mill certificate with every coil. | WcanFoshan, HongwangFoshan, Fulwealth SteelDongguan+3 more → | Process → | View → |
| ★Winding | Raw material | Enamelled Copper Wire | Polyesterimide / polyamide-imide, class 180, Ø0.3–0.7 mm | Per winding design | The Pearl River Delta has its own enamelled-wire makers in Zhuhai, Foshan, Jiangmen and Huizhou, alongside the big Anhui and Jiangsu producers. Local supply shortens lead time; still audit the thermal class and in-line test records per spool. | RonsenZhuhai, Jingda GuangdongFoshan, Suntek WireJiangmen+2 more → | Process → | View → |
| Stator insulation | Auxiliary material | Insulation Bobbin & Slot Liner | Epoxy powder coating, class F; or PA66+GF end insulators | Per stator | Shenzhen and Huizhou have makers of insulation films, sleeving and moulded bobbins; slot liners (DMD, NMN, PET film) are also stocked by Dongguan distributors. Confirm the thermal class matches the insulation system and keep UL file numbers on record. | FuweiHuizhou, WoerShenzhen, JDDShenzhen | Process → | View → |
| ★Magnets | Raw material | Sintered NdFeB Magnet | N35SH arc segments, Ni or Zn plated (ferrite for low-cost fans) | 14 pcs | Sintered blocks come mainly from Ningbo, Baotou and Ganzhou; Dongguan, Shenzhen and Jiangmen host magnet makers and finishing plants that cut, grind, coat and magnetise to drawing. Specify grade, coating and Hcj at temperature, and ask which plant sinters the block. | Dawa MagnetDongguan, Jiada MagnetDongguan, Courage MagnetDongguan+6 more → | Process → | View → |
| ★Rotor cup | Raw material | Deep-drawn Steel Motor Can | Deep-drawn SPCC / 08Al, 1.5–2 mm wall, ID run-out ≤ 0.05 mm | 1 pc | Dongguan, Shenzhen and Huizhou have deep-drawing stampers making motor cans close to the small-motor clusters. Check wall-thickness uniformity after drawing and the roundness of the bearing pocket. | HejuDongguan, Hongyuan HaojinShenzhen, RongguangHuizhou | Process → | View → |
| Magnet adhesive | Auxiliary material | Magnet Bonding Adhesive | Structural epoxy or acrylic, rated ≥ 150 °C | Per rotor | Huizhou, Dongguan and Shenzhen have domestic structural-adhesive makers that supply motor magnet bonding, next to local offices of international brands. Ask for shear strength at operating temperature and run a trial on your own rotor. | KafuterHuizhou, MaxAdhesiveDongguan, YaonengShenzhen+2 more → | — | View → |
| Shaft | Raw material | Motor Shaft | C45 or SUS420J2, ground, Ø8 h6 bearing seats | 1 pc | Dongguan is the Pearl River Delta centre for precision turned and ground shafts, with many CNC-turning and centreless-grinding shops serving the local motor industry. Check the h6 bearing-seat grinding capability and run-out inspection, not just turning. | Sanfeng ShaftsDongguan, LongmingDongguan, DayueDongguan | Process → | View → |
| ★Bearings | Purchased component | Deep-groove Ball Bearing | 608ZZ / 6000ZZ, C3 clearance, low-noise grease | 2 pcs | Bearing factories are mostly outside the Pearl River Delta (Zhejiang, Liaoning, Henan, Japan); the Pearl River Delta has brand sales offices in Guangzhou and Shenzhen and local makers of miniature bearings in Dongguan and Shenzhen. Buy branded bearings only through authorised channels to avoid counterfeits. | NSKGuangzhou, Fitrun BearingDongguan, Kentie BearingDongguan+6 more → | Process → | View → |
| Stator base with bearing tube | Raw material | Die-cast Aluminium End Cap | ADC12, machined bearing bores and stator seat | 1 pc | Foshan, Zhuhai and Dongguan have many high-pressure die-casters, from listed auto-parts groups to small motor-cap shops. Ask for X-ray porosity checks at the bearing seat and whether machining is done in-house. | JinjuqiweiFoshan, WencanFoshan, KingrunZhuhai+1 more → | Process → | View → |
| ★Hall sensor board (PCBA) | Sub-assembly | Hall Sensor Board (PCBA) | 3 latch-type Hall ICs on an FR-4 ring board at the stator base | 1 pc | SMT / EMS subcontractors in the Pearl River Delta (Shenzhen, Dongguan) and the Yangtze River Delta; many motor makers run their own small SMT line. | KingbrotherShenzhen, KaifaShenzhen, EDADOCShenzhen+1 more → | Process → | View → |
| Impregnating varnish (optional) | Auxiliary material | Impregnating Varnish | Polyesterimide or epoxy, class F | Per stator | International varnish makers run Pearl River Delta offices and blending sites (Zhuhai), and Foshan and Zhuhai have domestic insulating-resin producers. Choose varnish and process together — the supplier's process support matters as much as the product. | ELANTASZhuhai, DRDFoshan, ChangxianZhuhai+1 more → | — | View → |
| Lead cable & connector | Purchased component | Lead Wires & Connectors | UL2464 multi-core or UL1007 leads; JST / Molex or compatible | 1 set | Shenzhen and Dongguan are a major cluster for wire, harness and connector makers, including offices of international connector brands. Ask for crimp-force monitoring and pull-test records on terminated leads. | MolexShenzhen, WoerShenzhen, XSD CableDongguan+2 more → | Process → | View → |
| Fasteners & small parts | Auxiliary material | Fasteners & Small Parts | Circlip, wave washer, screws; zinc plated or stainless | 1 set | Dongguan and Shenzhen have many fastener makers and specialists in retaining rings and wave washers for small motors, so standard parts no longer have to come from Wenzhou or Ningbo. Check plating and hardness certificates per lot. | JinyiDongguan, LiangguDongguan, Lock TechnologyShenzhen+3 more → | Process → | View → |
How each key raw material and purchased component is made: process steps, the equipment and instruments used at each step with their main suppliers, and the technical control points. Click a material to expand.
Steelmaking & vacuum degassing → Hot rolling → Pickling & cold rolling → Continuous annealing → Insulation coating → Testing & slitting
Hot metal is refined in a converter, then RH-degassed to ultra-low carbon; silicon and aluminium are added to the target grade.
Technical control points:
Slabs are reheated and rolled into hot-rolled coils of about 2 mm.
Technical control points:
Scale is removed and the strip is cold-rolled to final gauge (0.50 / 0.35 mm).
Technical control points:
Recrystallization annealing in a protective atmosphere grows grains to the size that minimises core loss.
Technical control points:
A thin inorganic / organic insulation coating is applied and cured to limit interlaminar eddy currents and aid punchability.
Technical control points:
Magnetic properties are tested per coil, then coils are slit to the stamping width.
Technical control points:
Rod drawing → In-line annealing → Enamelling & curing → Lubrication, in-line testing & spooling
8 mm oxygen-free copper rod is drawn through successive diamond dies to the target diameter.
Technical control points:
Resistance annealing restores ductility after drawing.
Technical control points:
Base coat (polyesterimide) and overcoat (polyamide-imide) are applied in many thin passes, each cured in the oven.
Technical control points:
A surface lubricant is applied for winding, diameter and film faults are tested continuously, and wire is spooled.
Technical control points:
Resin drying → Injection moulding → Inspection
PA66+GF pellets are dried before moulding.
Technical control points:
Bobbins (end plates) are moulded, optionally with insert-moulded terminals.
Technical control points:
Dimensions, appearance and flammability conformance are checked.
Technical control points:
Melting & strip casting → Hydrogen decrepitation → Jet milling → Field orientation & pressing → Cold isostatic pressing → Sintering & ageing → Machining → Surface coating → Final inspection
Nd/Pr, Dy/Tb, Fe, B and additives are vacuum-induction melted and cast onto a water-cooled wheel into thin flakes.
Technical control points:
Flakes absorb hydrogen and crack along grain boundaries into coarse powder, followed by dehydrogenation.
Technical control points:
Coarse powder is milled in nitrogen to fine single-crystal particles.
Technical control points:
Powder is aligned in a strong magnetic field and pressed into blocks inside a protective glove box.
Technical control points:
Sealed green blocks are pressed isostatically to raise and even out density.
Technical control points:
Blocks are vacuum-sintered at about 1,050–1,100 °C, then aged in one or two stages to develop coercivity.
Technical control points:
Blocks are sliced, ground or wire-cut into arc segments, then chamfered and cleaned.
Technical control points:
Ni-Cu-Ni electroplating, zinc or epoxy coating protects the magnet from corrosion.
Technical control points:
Magnetic properties, dimensions and appearance are checked per lot.
Technical control points:
Blanking & deep drawing → Piercing, flanging & trimming → Cleaning & plating
Low-carbon steel strip is blanked and drawn into a can in several stages.
Technical control points:
Bushing boss, vent and mounting holes, tabs and the open edge are formed in the same transfer or progressive die.
Technical control points:
Cans are degreased and zinc or nickel plated (or blackened) for corrosion protection.
Technical control points:
Bar cutting → CNC turning & keyway / D-cut → Heat treatment → Cylindrical grinding → Cleaning, rust protection & inspection
Cold-drawn or ground bar stock (SUS420J2 / C45) is cut to length.
Technical control points:
Shoulders, grooves and the shaft extension are turned; the keyway or D-cut is milled.
Technical control points:
Quench and temper (or induction hardening of bearing seats) for strength and wear resistance.
Technical control points:
Bearing seats and the shaft extension are ground to h6 tolerance.
Technical control points:
Parts are cleaned, rust-protected and inspected before packing.
Technical control points:
Ring forging & turning → Heat treatment → Grinding → Superfinishing → Cleaning, assembly, greasing & sealing → Vibration & noise test
GCr15 (52100) bearing steel is forged or turned into ring blanks.
Technical control points:
Through-hardening and tempering to about HRC 60–64.
Technical control points:
Faces, outer diameter, bore and raceways are ground.
Technical control points:
Raceways are superfinished for low roughness and low noise.
Technical control points:
Rings and balls are cleaned, matched for clearance, assembled with the cage, greased and shielded.
Technical control points:
Every bearing is spun and its vibration measured to classify the grade.
Technical control points:
Melting & degassing → High-pressure die casting → Trimming & porosity inspection → CNC machining
ADC12 ingot is melted and degassed to reduce hydrogen porosity.
Technical control points:
Molten alloy is injected into the steel die at high speed and pressure.
Technical control points:
Gates and overflows are trimmed; castings are sampled by X-ray for porosity.
Technical control points:
Bearing seat, spigot and mounting faces are finish-machined.
Technical control points:
Solder-paste printing & SPI → Placement & reflow → AOI & electrical test → Lead-wire soldering & final inspection
Solder paste is printed through a stencil and its volume inspected.
Technical control points:
Hall ICs and passives are placed and reflow-soldered.
Technical control points:
Joints are optically inspected and boards functionally tested before depaneling.
Technical control points:
Lead wires are soldered to the board pads, sleeved or potted, and each board is checked before it goes to motor assembly.
Technical control points:
Cut, strip & crimp → Crimp verification → Housing insertion & continuity test
Wires are cut and stripped, and terminals crimped automatically.
Technical control points:
Cross-sections and pull tests verify each setup and lot.
Technical control points:
Terminals are inserted into connector housings and the harness is continuity-tested.
Technical control points:
Cold heading & thread rolling → Heat treatment & surface treatment → Optical sorting
Wire is cold-formed into screw blanks and threads are rolled.
Technical control points:
Parts are hardened as required, then zinc-plated or passivated.
Technical control points:
100% sorting removes dimensional and visual defects.
Technical control points:
Materials without a process here (bought-in chemicals, chips and some purchased components) are covered by incoming inspection and approval tests only.
Material-level tests are used for incoming inspection and supplier approval (PPAP / sample approval); motor-level tests for product validation (DV / PV). Conditions and criteria depend on the application and customer specification.
Applies to: Stator core
Applies to: Winding
Applies to: Stator insulation
Applies to: Magnets
Applies to: Rotor cup
Applies to: Magnet adhesive
Applies to: Shaft
Applies to: Bearings
Applies to: Stator base with bearing tube
Applies to: Hall sensor board (PCBA)
Applies to: Impregnating varnish (optional)
Applies to: Lead cable & connector
Applies to: Fasteners & small parts
| Test | Standard / condition |
|---|---|
| High-temperature operation and low-temperature start | IEC 60068-2-1 / -2-2 |
| Temperature cycling / thermal shock | IEC 60068-2-14 |
| Damp heat, steady state (e.g. 85 °C / 85% RH) | IEC 60068-2-78 |
| Salt spray | IEC 60068-2-11 |
| Sinusoidal / random vibration | IEC 60068-2-6 / -2-64 |
| Mechanical shock | IEC 60068-2-27 |
| Temperature-rise test | IEC 60034-1 |
| IP protection rating | IEC 60529 |
| Hipot and insulation resistance | IEC 60034-1 |
| Locked rotor and overload | Per customer specification |
| Endurance test (continuous rated load) | Per customer specification, typically 3,000–20,000 h |
| Noise and vibration | ISO 1680, IEC 60034-14 |
Low-voltage motor without electronics: Assumes a low-voltage motor (up to 48 V) without built-in electronics, exported as a component. An integrated driver or the end use (medical, automotive…) changes the requirements.
Listed alphabetically, not in order of preference. Confirm accreditation scope with each body.
Cost analysis, supplier sourcing and audits, production-line planning and equipment selection, and export certification planning — consulting by a senior motor engineer.
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