Manufacturing overview · Typical process
Hollow-shaft DDR / frameless torque motor · 36 slots / 32 poles (representative) · robot joint variant with strain-wave gear
Large-diameter, many-pole inner-rotor PMSM that drives the load directly with no gearbox: high torque at low speed, zero backlash and a large hollow bore for cables, air lines or optics. The housed DDR version adds a crossed-roller bearing and a high-resolution absolute encoder and is used on rotary indexing tables, wafer handlers, inspection stages and medical positioners. The robot joint module combines a frameless motor with a strain-wave (harmonic) gear, motor-side and output-side absolute encoders, a fail-safe brake and an integrated servo drive in one compact unit for collaborative robots, humanoids and AGV manipulators.
✓ Expert reviewed All content on this page has been reviewed by a senior motor engineer.
Click a model for full specifications and curves.
| Model | Voltage | Rated power | Rated torque | Rated speed | Current | Rated efficiency | Body length |
|---|---|---|---|---|---|---|---|
| HANS-B-003 | 220 V | 220 W | 3 N·m | 700 rpm | 1.5 A | — % | 65 mm |
| FI4-200-S-A-2 | 220 V | 2.09 kW | 200 N·m | 100 rpm | 6.5 A | — % | 150 mm |
| eRob90H100I | 48 V | 163 W | 51.9 N·m | 30 rpm | 6.7 A | — % | 123.8 mm |
11 main assembly steps. Each step lists its key equipment and instruments, their main suppliers, and the technical control points.
Thin-gauge electrical steel is punched into T-tooth segments in a progressive die and interlocked or bonded into stacks; burrs and stack tolerance directly affect cogging and iron loss at high pole counts.
Technical control points:
Each tooth segment receives an insulating bobbin or end plates plus slot liner and is wound individually with a high, orderly fill before being joined to its neighbours.
Technical control points:
Wound segments are joined into a full ring and pressed or shrink-fitted into the housing or a retaining ring; coils are connected in phase groups on a busbar ring or PCB by fusing or soldering, and the winding temperature sensor is fitted.
Technical control points:
After a 100% electrical test, the stator is vacuum-impregnated or potted with thermally conductive epoxy to bond the winding to the housing, then cured; the bore is finish-turned if specified.
Technical control points:
The thin-wall rotor ring is cleaned and primed; magnet segments are placed in a pole-pitch jig with dispensed adhesive so that pole spacing and radial height are held uniform, then cured. A glass-fibre bandage or sleeve may be added for higher speeds.
Technical control points:
Either the bonded rotor is magnetised in a multi-pole fixture matched to the pole count, or pre-magnetised segments are bonded with polarity guides; the surface field is then scanned around the full circumference.
Technical control points:
For the housed DDR, the crossed-roller bearing is fitted between rotor hub and housing in a clean area, clamping rings are tightened in a cross pattern to set preload, and runout and axial play are measured on the output face.
Technical control points:
The encoder ring or disk is centred on the rotor hub and the read head is set to the specified gap; an eccentricity / non-linearity compensation table is learned on a reference rotary stage and the commutation (electrical zero) offset is written to the encoder or drive.
Technical control points:
The wave generator is mounted on the motor shaft, the flexspline and circular spline are aligned and bolted with the output crossed-roller bearing, and the specified grease quantity is applied to teeth and wave-generator bearing; brake, output encoder and drive board are then fitted.
Technical control points:
The finished joint is run in, then lost motion and torsional stiffness are measured by loading the output in both directions; dual-encoder offset and transmission-error compensation are learned, and the integrated drive is flashed and parameterised.
Technical control points:
100% electrical-safety test and motor characterisation on a torque test bench, plus angular accuracy and repeatability against a reference encoder; joint modules additionally pass a powered run-in.
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. Segment lamination stamping & stacking
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. Segment lamination stamping & stacking
Equipment page →Verifies dimensions, geometry and runout.
Selection criteria: Measurement uncertainty, probing system.
Used in: 1. Segment lamination stamping & stacking, 3. Stator ring assembly & connection, 5. Rotor magnet bonding, 7. Crossed-roller bearing installation & preload, 8. Encoder mounting & calibration, 9. Strain-wave gear assembly & lubrication (joint module)
Equipment page →Inserts slot-liner insulation into stator slots.
Selection criteria: Slot geometry range, cycle time, paper forming method.
Used in: 2. Segment insulation & winding
Equipment page →Winds concentrated coils on inner-rotor stators.
Selection criteria: Spindles, wire-diameter range, tension control, layering accuracy.
Used in: 2. Segment insulation & winding
Equipment page →Rotor-to-shaft and bearing press-fits with force–displacement monitoring.
Selection criteria: Force / displacement resolution, curve evaluation windows.
Used in: 3. Stator ring assembly & connection, 7. Crossed-roller bearing installation & preload, 9. Strain-wave gear assembly & lubrication (joint module)
Equipment page →Joins enamelled wire to terminals without pre-stripping.
Selection criteria: Closed-loop control of current, force and time; joint monitoring.
Used in: 3. Stator ring assembly & connection
Equipment page →Winding resistance, turn-to-turn insulation, hipot and insulation resistance.
Selection criteria: Surge voltage, waveform-comparison algorithm, test cycle time.
Used in: 4. Stator test, potting & curing
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: 4. Stator test, potting & curing
Equipment page →Applies adhesive for bonding rotor magnets.
Selection criteria: Shot-volume accuracy, 1K / 2K adhesive capability.
Used in: 4. Stator test, potting & curing, 5. Rotor magnet bonding, 9. Strain-wave gear assembly & lubrication (joint module)
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: 6. Magnetising
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: 8. Encoder mounting & calibration, 10. Joint calibration: backlash, stiffness & accuracy, 11. End-of-line test
Equipment page →Checks assembled boards for shorts, opens and component values (ICT), programs the firmware, and tests the board's functions under power (FCT).
Selection criteria: Bed-of-nails fixture design, test coverage, programming interface, cycle time, data logging and traceability.
Used in: 10. Joint calibration: backlash, stiffness & accuracy
Equipment page →End-of-line electrical safety tests.
Selection criteria: Output voltage, leakage-current resolution.
Used in: 11. End-of-line test
Equipment page →Runs boards or motors under power at elevated temperature for hours to screen out early failures.
Selection criteria: Temperature uniformity, number of channels, load and power-cycling control, monitoring and logging.
Used in: 11. 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 segments | Raw material | Non-oriented Electrical Steel | Thin-gauge non-oriented steel, 0.2–0.35 mm (e.g. 35W300 or 20/25-gauge high-frequency grades) | 36 segments per 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 | Class 180–200 enamelled copper, polyesterimide / polyamide-imide, Ø0.4–1.2 mm | Per frame size | 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 → |
| ★Magnets | Raw material | Sintered NdFeB Magnet | N42SH / N45SH (150 °C), thin arc or flat segments, Ni or epoxy coated | 32 pcs (one per pole, more if segmented axially) | 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 ring / hollow hub | Raw material | Motor Shaft | Low-carbon or alloy steel (magnetic back-iron), turned and ground; hollow bore per drawing | 1 | 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 → |
| ★Crossed-roller bearing | Purchased component | Deep-groove Ball Bearing | Thin-section crossed-roller bearing, P5 or better, preloaded (C1 / zero clearance) | 1 (DDR); 1 at gear output (joint) | 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 → |
| ★Absolute encoder | Bought-in part | — | Optical disk or magnetic ring with read head, 20–26 bit, BiSS-C or other bidirectional serial protocol | 1 (DDR); 2 (joint) | — | — | — | — |
| ★Strain-wave gear set (joint) | Purchased component | Gearbox Gears (sintered steel / plastic) | Cup or hat-type flexspline, circular spline and wave generator; ratio 50–160:1, lost motion ≤ 1 arcmin | 1 set | Dongguan has a dense powder-metallurgy and plastic-gear cluster, and Shenzhen has gearbox specialists for micro gear motors. Ask for gear-roll test data and noise checks on assembled gearboxes. | Jingsheng PMDongguan, Qiantong PMDongguan, UT GearShenzhen+1 more → | Process → | View → |
| ★Gear grease (joint) | Auxiliary material | Gearbox Grease | Grease specified for strain-wave gears, low-temperature capable | Per gear maker's quantity | Dongguan, Foshan and Shenzhen have domestic grease makers next to Pearl River Delta offices of German and Japanese specialty brands. Check low-temperature torque and compatibility with plastic gears. | BaoxingDongguan, CaidonFoshan, HechengShenzhen+1 more → | — | View → |
| ★Fail-safe brake (joint) | Bought-in part | — | Spring-applied electromagnetic brake, 24 V DC, holding torque ≥ rated motor torque | 1 | — | — | — | — |
| ★Integrated servo drive board (joint) | Purchased component | Printed Circuit Board (bare board) | Multilayer FR-4 with MCU, gate drivers and MOSFET bridge, EtherCAT / CANopen; conformal coated | 1 | The Pearl River Delta (Shenzhen, Huizhou, Zhuhai, Jiangmen, Guangzhou) is one of the world's largest PCB bases, from quick-turn prototype shops to listed volume makers. For motor boards, check copper thickness, Tg and solder-mask quality near the Hall sensor. | SuntakShenzhen, KinwongShenzhen, FastprintGuangzhou+1 more → | — | View → |
| Housing | Raw material | Aluminium Extruded Housing | 6061-T6 machined, hard or black anodized; bearing and stator seats finish-machined | 1 | Foshan (Nanhai, Dali) is China's largest aluminium-extrusion cluster, with more in Zhaoqing and Jiangmen; most extruded motor housings in South China are made there. Machining of the bore and spigot is often done by a second shop — agree who owns concentricity. | Honstar AluminumFoshan, Guoyao AluminiumZhaoqing, Kam KiuJiangmen | Process → | View → |
| Insulation | Auxiliary material | Insulation Bobbin & Slot Liner | Segment bobbins / end plates PA66+GF or LCP UL94 V-0; slot liner NMN / aramid paper, class F / H | 1 set | 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 → |
| ★Potting / impregnating resin | Auxiliary material | Potting Compound / Conformal Coating | Thermally conductive epoxy (≥ 0.8 W/m·K), class F / H | Per stator volume | Guangdong has the densest cluster of potting, conformal-coating and adhesive makers in China (Dongguan, Shenzhen, Guangzhou, Foshan, Zhuhai). Check cure shrinkage and CTE against the components on your board. | MaxAdhesiveDongguan, YaonengShenzhen, BornsunShenzhen+4 more → | — | View → |
| Magnet adhesive | Auxiliary material | Magnet Bonding Adhesive | Structural epoxy / acrylic, rated ≥ 150 °C, with primer | Small amount | 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 → |
| Cables & connectors | Purchased component | Lead Wires & Connectors | Shielded power and encoder cables, high-flex for robots; M17 / M23-type or board connectors | 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 | Bearing clamping-ring screws, dowel pins, O-rings, temperature sensor (PTC / KTY / PT1000) | 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:
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:
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:
Mixing & compacting → Sintering → Sizing → Heat treatment → Final inspection
Iron-based powder (e.g. Fe-Cu-C) is mixed with lubricant and compacted into gear shapes.
Technical control points:
Compacts are sintered in a protective atmosphere, bonding the particles.
Technical control points:
Sintered gears are re-pressed in a sizing die to improve accuracy and surface finish.
Technical control points:
Highly loaded output-stage gears are case-hardened or steam-treated for wear resistance.
Technical control points:
Gears are checked for composite deviation, bore size and appearance.
Technical control points:
Billet heating & extrusion → Stretching, cutting & ageing → CNC machining → Anodizing
6063 billets are heated and extruded through a die into the square housing profile, quenched at the press.
Technical control points:
Profiles are stretched straight, cut to length and artificially aged to T5.
Technical control points:
Spigot, bore, mounting holes and slots are machined.
Technical control points:
Parts are anodized (and optionally dyed) for corrosion protection and appearance.
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:
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 segments
Applies to: Winding
Applies to: Magnets
Applies to: Rotor ring / hollow hub
Applies to: Crossed-roller bearing
Applies to: Strain-wave gear set (joint)
Applies to: Gear grease (joint)
Applies to: Integrated servo drive board (joint)
Applies to: Housing
Applies to: Insulation
Applies to: Potting / impregnating resin
Applies to: Magnet adhesive
Applies to: Cables & connectors
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 |
Motor for high-voltage drives: Covers motors sold in low-voltage and high-voltage versions. Versions driven above 75 V DC / 50 V AC (e.g. from 220 V AC drives) fall under low-voltage-directive safety rules and need reinforced insulation and hipot evidence.
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.
Discuss on WhatsApp