Manufacturing overview · Typical process
Ø16–22 mm · 6 / 12 / 24 V · 9,000–15,000 rpm no-load · ironless rotor, no cogging
A high-speed, low-inertia precision drive used in medical pumps and handpieces, personal-care appliances, smart locks and robot joints. The rotor is a self-supporting skewed (rhombic) copper coil with no iron, spinning between a stationary NdFeB magnet and the steel housing. With no iron in the rotor there is no cogging and very low iron loss, so efficiency is high and acceleration is fast. Quality is decided by coil geometry and bonding, the commutation system (precious-metal or graphite brushes), rotor balance and bearing quality, which together set speed, current, noise and life.
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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 |
|---|---|---|---|---|---|---|---|
| TDC2230-24120 | 24 V | 8.75 W | 0.00785 N·m | 10,643 rpm | 0.478 A | 76.3 % | 31 mm |
| TDC1625-1290 | 12 V | 1.12 W | 0.00147 N·m | 7,259 rpm | 0.18 A | 51.6 % | 24.6 mm |
11 main assembly steps. Each step lists its key equipment and instruments, their main suppliers, and the technical control points.
Self-bonding enamelled wire is wound on a mandrel into a skewed or rhombic self-supporting winding, either flat (then rolled) or directly as a cylinder, with taps brought out for each commutator segment.
Technical control points:
The winding is pressed to its final wall thickness, bonded by heating the self-bonding layer (current or hot air), then impregnated with epoxy and oven-cured into a rigid thin-walled cup.
Technical control points:
The cured coil is bonded to the commutator carrier disc, and the shaft is pressed into the carrier so that coil, commutator and shaft are concentric.
Technical control points:
Coil taps are stripped and soldered or micro-welded to the commutator segments, then the joints are secured with adhesive.
Technical control points:
Every rotor is checked for open or shorted coils and for insulation between the winding and the shaft.
Technical control points:
Because the rotor runs above 10,000 rpm, it is dynamically balanced in two planes, usually by adding a small amount of balancing epoxy or removing material from the carrier.
Technical control points:
The cylindrical NdFeB magnet is bonded onto the central bearing tube of the flange and magnetized diametrically into 2 poles, aligned with the brush position.
Technical control points:
Miniature ball bearings or sintered bushings are pressed into the bearing tube and end cap, with a spring washer or shims to set preload and axial play.
Technical control points:
Precious-metal brush springs or graphite brushes with springs are fitted to the terminals in the plastic end cap, and any suppression component is soldered in.
Technical control points:
The rotor is slid over the magnet into the housing, the brush end cap is fitted over the commutator, and the housing is crimped or laser-welded to the flange and end cap.
Technical control points:
Motors are run in so the brushes bed to the commutator, then each motor is tested for speed, current, starting voltage, current ripple and noise before packing.
Technical control points:
Suppliers are representative examples (international / mainland China), not an exhaustive or endorsed list.
Winds the coils of brushed-motor armatures with one or two flyers and hooks the wire onto the commutator tangs between coils.
Selection criteria: Number of flyers, slot and commutator-bar count range, wire size range, hooking reliability, changeover time.
Used in: 1. Coil winding
Equipment page →Applies adhesive for bonding rotor magnets.
Selection criteria: Shot-volume accuracy, 1K / 2K adhesive capability.
Used in: 2. Coil forming & curing, 3. Rotor assembly, 6. Rotor balancing, 7. Magnet bonding & magnetizing
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: 2. Coil forming & curing
Equipment page →Verifies dimensions, geometry and runout.
Selection criteria: Measurement uncertainty, probing system.
Used in: 2. Coil forming & curing, 3. Rotor assembly, 8. Bearing press-fit, 10. Final assembly
Equipment page →Rotor-to-shaft and bearing press-fits with force–displacement monitoring.
Selection criteria: Force / displacement resolution, curve evaluation windows.
Used in: 3. Rotor assembly, 8. Bearing press-fit, 10. Final assembly
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. Commutator connection, 9. Brush end-cap assembly
Equipment page →Joins enamelled wire to terminals without pre-stripping.
Selection criteria: Closed-loop control of current, force and time; joint monitoring.
Used in: 4. Commutator connection, 9. Brush end-cap assembly
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. Rotor electrical test
Equipment page →End-of-line electrical safety tests.
Selection criteria: Output voltage, leakage-current resolution.
Used in: 5. Rotor electrical test, 11. Run-in & end-of-line test
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: 6. Rotor balancing
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: 7. Magnet bonding & magnetizing
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: 11. Run-in & 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 |
|---|---|---|---|---|---|---|---|---|
| ★Rotor coil | Raw material | Enamelled Copper Wire | Self-bonding polyurethane enamelled copper wire, Ø0.05–0.2 mm | 1 coil (5 sections) | 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 → |
| ★Coil impregnation epoxy | Auxiliary material | Impregnating Varnish | Low-viscosity heat-curing epoxy, Class F or higher | As required | 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 → |
| ★Magnet | Raw material | Sintered NdFeB Magnet | Cylindrical sintered NdFeB, diametrically magnetised, e.g. N38SH–N42SH, nickel or epoxy coated | 1 | 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 → |
| Magnet adhesive | Auxiliary material | Magnet Bonding Adhesive | Anaerobic or heat-curing structural adhesive; also used for coil-to-carrier bonding | As required | 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 → |
| Housing | Raw material | Deep-drawn Steel Motor Can | Low-carbon steel tube or deep-drawn can (magnetic return path), nickel or zinc plated | 1 | 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 → |
| Front flange & bearing tube | Bought-in part | — | Machined brass or stainless steel, with M2 / M3 mounting threads | 1 | — | — | — | — |
| ★Commutator | Purchased component | Commutator (hook type) | 5-segment plate commutator; precious-metal alloy (silver / gold based) or copper segments in a plastic carrier | 1 | Shenzhen and Dongguan host commutator makers including a listed specialist, alongside the big Zhejiang and Jiangsu producers. Ask for over-speed (spin) test results and bar-to-bar insulation data. | HuanxiangDongguan, KaizhongShenzhen, SOMPShenzhen | — | View → |
| ★Brushes & brush end cap | Purchased component | Carbon Brushes & Brush Gear | Precious-metal multi-finger spring brushes or copper-graphite brushes; PBT / PA end cap (UL 94 V-0 where required) | 1 set | Guangzhou, Zhuhai and Dongguan have carbon-brush and brush-holder makers, including Japanese-invested plants. Match brush grade to current density and commutator speed, and test wear on your own motor. | Fuji CarbonGuangzhou, EckerleZhuhai, LinhengDongguan+1 more → | — | View → |
| Shaft | Raw material | Motor Shaft | Hardened and ground stainless steel, Ø2–3 mm, tight diameter and roundness tolerance | 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 → |
| ★Bearings | Purchased component | Deep-groove Ball Bearing | Miniature deep-groove ball bearings (e.g. 3 × 7 × 3 mm), low-noise grade, high-speed grease | 2 | 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 → |
| Sintered bushings (alternative) | Purchased component | Oil-impregnated Sintered Bushing | Oil-impregnated sintered bronze, for low-cost or low-noise versions instead of ball bearings | 0–2 | Dongguan's powder-metallurgy plants make oil-impregnated bushings for small motors in high volume. Check oil content, porosity and the bore size after press-fit. | Jingsheng PMDongguan, Qiantong PMDongguan, Ningzhi PMDongguan | — | View → |
| Spark suppression | Purchased component | Passive Components (chip resistors, MLCC) | Varistor ring on the commutator or chip capacitors across the terminals | Optional | Zhaoqing, Shenzhen and Dongguan host chip-resistor and MLCC makers, and Shenzhen's Huaqiangbei and Futian are the distribution hub for Japanese, Korean and Taiwanese brands. Use authorised channels and avoid the spot market for production lots. | FenghuaZhaoqing, EYANGShenzhen, MilliohmShenzhen+1 more → | — | View → |
| Terminals & leads | Purchased component | Lead Wires & Connectors | Solder tabs or leads with connector per customer | 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 → |
| Small parts | Auxiliary material | Fasteners & Small Parts | Spring washers, shims, retaining rings and balancing epoxy | 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.
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:
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:
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: Rotor coil
Applies to: Coil impregnation epoxy
Applies to: Magnet
Applies to: Magnet adhesive
Applies to: Housing
Applies to: Commutator
Applies to: Brushes & brush end cap
Applies to: Shaft
Applies to: Bearings
Applies to: Sintered bushings (alternative)
Applies to: Spark suppression
Applies to: Terminals & leads
Applies to: 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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