Magnetic Compound
Br 0.20–0.78 T · Hcb 160–520 kA/m · Hcj 400–1,120 kA/m — bonded ferrite or bonded NdFeB selected according to the required magnetic output and operating temperature.
Bonded Magnet System
Bonded Magnet Rotor Manufacturer
GX Magnet makes custom bonded magnet rotors from customer drawings. Injection-molded and compression-bonded options support multipole magnetization, built-in inserts and reliable mechanical fit.
- Bonded ferrite or bonded NdFeB selected for the application
- Pole count, magnetic pattern, inserts, sleeves and shaft interfaces defined by the drawing
- Approved samples and agreed magnetic inspection requirements guide batch production
Project screening
What to Define Before Requesting a Bonded Rotor Quote
A bonded rotor review begins with the magnetic compound, molding route, pole pattern, mechanical insert and operating conditions—not just the outside dimensions.
- Supply form
- Bonded magnetic rotor, molded magnet ring or insert-integrated rotor
- Material route
- Bonded ferrite or bonded NdFeB evaluated against the magnetic and environmental requirements
- Design focus
- Pole geometry, insert bonding, rotor runout, retention and the working air gap
- Required information
- 2D/3D drawings, magnetic target, pole map, speed, operating environment and annual demand
GX Bonded Magnet Rotor Product Range
GX provides drawing-based bonded magnet rotors for motors, pumps, sensors, appliances and automotive actuators. Bonded ferrite or bonded NdFeB can be molded around a shaft, hub or insert to integrate complex geometry with a defined multipole pattern. Each rotor is developed around the required dimensions, magnetic waveform, operating temperature, speed and assembly interface.
Injection-Molded Ferrite Rotor
Material and Process:
Ferrite magnetic powder compounded with PA12 or PPS polymer binder and injection-molded.
Key Features:
Lowest-cost route; high design freedom; can integrate a shaft or metal insert during molding; inherently corrosion-resistant and typically requires no electroplating.
Typical Applications:
Dishwasher pumps, washing-machine pumps, air-conditioning fans, stepper motors, toy motors and small household-appliance motors.
Ferrite magnetic powder compounded with PA12 or PPS polymer binder and injection-molded.
Key Features:
Lowest-cost route; high design freedom; can integrate a shaft or metal insert during molding; inherently corrosion-resistant and typically requires no electroplating.
Typical Applications:
Dishwasher pumps, washing-machine pumps, air-conditioning fans, stepper motors, toy motors and small household-appliance motors.
Injection-Molded NdFeB Rotor
Material and Process:
Rapidly solidified NdFeB powder compounded with PA12 or PPS polymer binder and injection-molded.
Rapidly solidified NdFeB powder compounded with PA12 or PPS polymer binder and injection-molded.
Key Features:
Higher magnetic output than injection-molded ferrite; dimensional tolerances of ±0.01–0.05 mm; net-shape molding of complex geometries; good toughness and vibration resistance.
Higher magnetic output than injection-molded ferrite; dimensional tolerances of ±0.01–0.05 mm; net-shape molding of complex geometries; good toughness and vibration resistance.
Typical Applications:
Smartphone camera VCM image-stabilization motors, linear vibration motors, automotive electronic stepper motors, EPS sensors and precision-instrument micromotors.
Smartphone camera VCM image-stabilization motors, linear vibration motors, automotive electronic stepper motors, EPS sensors and precision-instrument micromotors.
Compression-Bonded NdFeB Rotor
Material and Process:
Rapidly solidified NdFeB powder mixed with 3%–5% epoxy resin, compression-molded and cured.
Key Features:
High magnetic-powder loading of 75%–82%; higher density, magnetic flux and dimensional stability than injection-molded bonded magnets. Under comparable conditions, magnetic output can be 30%–50% higher than injection-molded NdFeB.
Typical Applications:
HDD spindle motors, voice-coil motors, high-end servo motors and precision optical encoder rings.
Key Features:
High magnetic-powder loading of 75%–82%; higher density, magnetic flux and dimensional stability than injection-molded bonded magnets. Under comparable conditions, magnetic output can be 30%–50% higher than injection-molded NdFeB.
Typical Applications:
HDD spindle motors, voice-coil motors, high-end servo motors and precision optical encoder rings.
Precision Multipole Bonded Rotor
Material and Process:
Bonded NdFeB or bonded ferrite combined with a precision multipole magnetizing fixture. Radial, axial and other drawing-defined magnetization configurations, including Halbach-type patterns where feasible, can be evaluated.
Bonded NdFeB or bonded ferrite combined with a precision multipole magnetizing fixture. Radial, axial and other drawing-defined magnetization configurations, including Halbach-type patterns where feasible, can be evaluated.
Key Features:
Custom pole counts from 2 to over 100; controlled pole uniformity to help reduce motor torque ripple; net-shape molding with ±0.01–0.05 mm tolerances and little or no secondary grinding.
Custom pole counts from 2 to over 100; controlled pole uniformity to help reduce motor torque ripple; net-shape molding with ±0.01–0.05 mm tolerances and little or no secondary grinding.
Typical Applications:
Encoder ring magnets, Hall-sensor rings, multipole BLDC rotors, precision stepper-motor rotors and flowmeter magnetic rotors.
Encoder ring magnets, Hall-sensor rings, multipole BLDC rotors, precision stepper-motor rotors and flowmeter magnetic rotors.
Insert-Molded Bonded Magnetic Rotor with Shaft or Metal Inserts
Material and Process:
Ferrite or NdFeB powder with a PA12 or PPS binder is injection-molded directly around a shaft, brass bushing or other metal insert.
Ferrite or NdFeB powder with a PA12 or PPS binder is injection-molded directly around a shaft, brass bushing or other metal insert.
Key Features:
Eliminates separate press fitting, reduces cracking risk and supports compact integrated structures. Polymer encapsulation provides corrosion protection, toughness and vibration resistance. Shaft-to-rotor coaxiality can be specified to ≤0.02 mm.
Eliminates separate press fitting, reduces cracking risk and supports compact integrated structures. Polymer encapsulation provides corrosion protection, toughness and vibration resistance. Shaft-to-rotor coaxiality can be specified to ≤0.02 mm.
Typical Applications:
Appliance and aquarium pumps, cooling fans, automotive actuators and sensors, small appliance motors, optical encoders and flowmeter rotors.
Appliance and aquarium pumps, cooling fans, automotive actuators and sensors, small appliance motors, optical encoders and flowmeter rotors.
Overmolded Bonded Magnet Rotor
Material and Process:
Compact pumps, cooling fans, appliance motors, automotive actuators, sensor and encoder rotors, flowmeters and other integrated multipole rotor assemblies.
Key Features: Compact pumps, cooling fans, appliance motors, automotive actuators, sensor and encoder rotors, flowmeters and other integrated multipole rotor assemblies.
This process integrates the magnetic body and mechanical interface. Compound selection, insert retention, molding shrinkage, rotor OD, coaxiality, TIR, pole position and magnetic waveform are controlled according to the drawing.
Typical Applications:
Compact pumps, cooling fans, appliance motors, automotive actuators, sensor and encoder rotors, flowmeters and other integrated multipole rotor assemblies.
Compact pumps, cooling fans, appliance motors, automotive actuators, sensor and encoder rotors, flowmeters and other integrated multipole rotor assemblies.
Product and supply scope
What Is a Bonded Magnet Rotor?
A bonded magnet rotor is made by combining magnetic powder with a polymer binder and then molding or compacting the mixture into the required rotor geometry. The process can produce multipole patterns, thin sections, integrated inserts and complex shapes that may be difficult to achieve with separately assembled sintered magnets.
GX evaluates bonded ferrite and bonded NdFeB options for each project. Magnetic output, operating temperature, mechanical strength, moisture exposure, insert design, magnetization pattern and production volume must be considered together before the material and process are confirmed.
Drawing-based supplyThe rotor envelope, magnetic body, insert, sleeve, shaft features and datums are finalized before sample release.
Compound selectionThe magnetic powder, binder system and molding route are selected according to the required output, temperature and mechanical performance.
Magnetization approvalPole count, pole position, waveform or functional response is verified against the approved sample and test method.
Supply boundaryStators, bearings, electronics and complete motor assembly are excluded unless specifically included in the approved scope.
Rotor design variables
Define the Bonded Rotor Around Its Magnetic and Molding Requirements
The magnetic compound, rotor geometry, inserts, magnetization pattern and operating conditions must be combined in one manufacturable specification.
Engineering data
Bonded Magnet Rotor Design Parameters
The final specification is based on the bonded material system, molding route, insert design, pole map, operating speed, service environment and validation plan.
| Parameter | Specification / Review Basis |
|---|---|
| Structure / Supply Scope | 2–64 poles · injection-molded or compression-bonded construction — magnetic ring or sleeve, or a bonded rotor integrated with a shaft, hub or insert. |
| Magnetic Compound | Br 0.20–0.78 T · Hcb 160–520 kA/m · Hcj 400–1,120 kA/m · (BH)max 12–92 kJ/m³ — combined reference ranges for bonded ferrite and bonded NdFeB; they do not represent a single compound. |
| Dimensions / Inserts | OD Ø8–120 mm · ID Ø2–80 mm · length 5–80 mm · shaft Ø2–30 mm · IT6–IT9 tolerance grades — final insert and overmold geometry follows the approved drawing. |
| Poles / Magnetic Output | 2–64 poles · radial, axial or multipole magnetization · pole-position tolerance ±1°–±3° — magnetic flux and waveform are measured using an agreed fixture, distance and temperature. |
| Geometric Accuracy | Concentricity 0.02–0.15 mm · TIR 0.03–0.20 mm · Ra 0.8–3.2 μm — the molding datum and air-gap surface are inspected together. |
| Mechanical / Rotational | Retention force 30–2,000 N · torque 0.05–50 N·m · balance grade G1–G6.3 · rated speed ≤15,000 rpm · maximum speed ≤20,000 rpm — limits depend on the binder, insert design and wall thickness. |
| Environment / Acceptance | Maximum operating temperature 100–150°C, depending on the compound and rotor design · salt-spray exposure 24–240 h · overspeed factor 1.2× · AQL 0.65–1.5 — final test and sampling plans are project-defined. |
These are typical review ranges only. Magnetic properties vary by compound and density; final rotor limits are confirmed in the approved material specification and drawing and under the agreed test conditions.
Application examples
Bonded Magnet Applications in Automotive and Appliance Systems
These examples show how bonded magnet materials, molded structures, magnetization patterns and inspection methods are adapted to the functional requirements of each application.
Case 01
Angle Sensor Magnet
- Application: angular-position sensing
- Multipole magnetization on one face produces a saddle-shaped field waveform
- Hot- and cold-runner systems are selected to suit the molding process
- Mold-flow analysis is used to optimize the tooling and process parameters
- Magnetic flux is checked by automated 100% inspection
- Cleanroom production supports the specified cleanliness requirements
Case 02
Steering-Wheel Audio Switch
- Application: steering-wheel audio control
- 12 radial poles with an outer diameter of 8 mm
- Two-stage injection molding forms the magnetic element first and then the surrounding component
- Mold-flow analysis is used to optimize the tooling and molding process
- Magnetic-field simulation is used to evaluate performance and identify potential design risks
Case 03
Power Sliding-Door Sensor Magnet
- Application: power sliding-door system
- Injection-molded bonded NdFeB magnet
- 64-pole magnetization on one face
- Mold-flow analysis is used to optimize the tooling and molding process
Case 04
Dishwasher Pump Rotor
- Application: dishwasher pump motor
- Eight-pole design with a sinusoidal field waveform
- Specified balance-correction mass: ≤15 mg per correction plane
Manufacturing route
From Design Review to Controlled Bonded-Rotor Production
Compound selection, molded geometry, inserts, magnetization and inspection are managed against one approved rotor specification.
Requirements Review
The drawing, motor type, magnetic target, pole map, speed, operating environment and demand are reviewed together.
Compound Selection
Bonded ferrite or bonded NdFeB and the binder system are evaluated against the application requirements.
Tooling and Insert Review
The parting line, molding shrinkage, insert retention, gate locations and critical datums are defined.
Molding or Compaction
The magnetic body and approved insert structure are produced under controlled process conditions.
Magnetization and Testing
The pole pattern, field waveform, dimensions, runout and agreed mechanical characteristics are verified.
Production and Batch Control
The approved drawing, sample, process parameters and inspection plan govern recurring production.
Verification
Verify the Pole Pattern, Molded Geometry and Rotor Function
The inspection plan links the molded magnetic body and insert geometry to pole position, runout, retention and the rotor’s intended function.
| Inspection item | Control method | Purpose |
|---|---|---|
| Molded dimensions | Critical dimensions, bore, OD, datums and insert position checked using the agreed methods | Controls mechanical fit and air-gap consistency |
| Concentricity / runout | Magnetic surface and shaft or insert datums evaluated where specified | Supports stable rotation |
| Magnetic output | Magnetic flux, field waveform or an agreed functional characteristic measured under defined conditions | Verifies the compound and magnetization process |
| Pole position | Pole count, sequence and circumferential position verified against the approved pole map | Helps prevent commutation errors |
| Retention / appearance | Insert security, cracks, flash, joints and contamination evaluated to the agreed criteria | Reduces mechanical and assembly risks |
Applications
Bonded Magnet Rotors for OEM Motor and Sensor Designs
Bonded magnet rotors suit projects requiring controlled multipole magnetization, compact geometry, integrated inserts or repeatable magnetic positioning.
Automotive Actuators
Compact rotors evaluated for pole position, operating temperature, insert retention and recurring production requirements.
Pump and Valve Motors
Moisture and chemical exposure, sealing interfaces, operating speed and magnetic response are defined for each project.
Encoders and Sensors
Pole pitch, field waveform, concentricity and the installed air gap form the basis for acceptance.
Compact BLDC Motors
Rotor geometry, multipole magnetization, runout and fit with the mating stator are reviewed together.
Quality-system support
Quality Controls for Bonded Magnet Rotor Programs
Drawing revision control, material-lot traceability, sample approval and project-specific inspection planning form the quality framework from incoming materials through finished-product shipment. Statistical process control (SPC), measurement-system analysis (MSA) and process-capability studies (Cpk) are applied to agreed critical characteristics to support dimensional consistency, stable magnetic output and assembly reliability from prototype validation through recurring production.
Drawing Revision and Change Control
Magnet geometry, geometric tolerances—including coaxiality, radial or total indicated runout (TIR), and cylindricity—pole layout, pole-to-pole variation, magnet retention and visual standards are controlled to the latest customer-approved drawing revision.
Engineering change notices (ECNs) and 4M change management—Man, Machine, Material and Method—are applied. Any change requires technical review, first-article validation and written customer approval before production release, ensuring that manufacturing and customer requirements remain aligned.
Production Release Baseline
Before recurring production is released, the project provides a full dimensional inspection report (FAI), magnetic test report, material Certificate of Analysis (COA), visual limit samples and process-capability data (Cpk).
Prototype records cover critical dimensions; material magnetic properties including Br, Hcj and (BH)max; finished-rotor flux distribution; fit tolerances; radial runout; and dynamic-balance results. These mutually approved records establish the production baseline. For agreed critical characteristics, a Cpk target of ≥1.33 is used to control variation between production batches and approved samples.
Production Inspection and SPC Control
Before production begins, the control plan, inspection work instructions, measurement methods and equipment, AQL sampling level and acceptance criteria are confirmed with the customer.
The inspection flow includes incoming quality control (IQC), in-process quality control (IPQC)—including molding-parameter monitoring, first-article inspection and scheduled in-process checks—finished quality control (FQC) and outgoing quality control (OQC). SPC control charts monitor critical dimensional and magnetic characteristics. Abnormal trends trigger early warning and corrective and preventive action (CAPA). Inspection data can be traced to the production batch, mold cavity and raw-material lot.
Project-specific inspection records and magnetic-performance data can be provided during sample approval or project review, based on the approved drawing and agreed acceptance criteria.
Technical consultation
Discuss Your Bonded Magnet Rotor Project in Person
At industrial exhibitions, GX Magnet presents magnetic materials, rotor assemblies and motor-component capabilities to OEM buyers, engineers and sourcing teams.
Bring your bonded magnet rotor drawing and information about the mating components. An initial discussion can clarify the supply boundary, identify interface risks and establish the information needed for a formal engineering review.
Sample Review
Compare magnet layouts, shaft or hub interfaces and rotor designs before selecting the most suitable quotation route.
Engineering Discussion
Review the air gap, speed, runout, balance, operating environment and validation requirements.
Supplier Evaluation
Plan the drawing review, sample approval, inspection records and communication for recurring production.
GX Magnet
Magnetic Materials and Motor Components Since 1992
GX Magnet’s integrated manufacturing resources combine ferrite-material experience, bonded magnet production and drawing-based rotor project support for automotive, appliance, pump, HVAC and industrial applications.
Material and Design Review
The magnet material, pole layout, rotor structure and retention method are evaluated against the application requirements.
Drawing-Based Production
Mechanical interfaces, approved samples and inspection criteria are controlled against the released drawing revision.
OEM Project Support
Engineering and sourcing teams receive a clear RFQ checklist and a project-specific definition of the supply scope.
FAQ
Bonded Magnet Rotor Sourcing Questions
Clarify the drawing, material, interfaces, validation requirements and production basis before approving a custom bonded rotor source.
When should I choose a bonded magnet rotor instead of a sintered-magnet rotor?
A bonded magnet rotor is often considered when the design requires complex geometry, thin sections, integrated inserts, controlled multipole positioning or fewer secondary assembly operations. The available magnetic output, operating temperature and mechanical requirements must still be evaluated against the motor specification.
How do we choose between bonded ferrite and bonded NdFeB?
The choice depends on the required magnetic output, operating temperature, moisture or chemical exposure, rotor volume, mechanical load and cost target. GX evaluates the magnetic compound and binder system against the application rather than selecting a material by product name alone.
Can the magnet be molded directly around a shaft or metal insert?
Yes, subject to a review of the insert material, surface condition, knurl or undercut, wall thickness, molding shrinkage, torque transfer, runout datum and retention requirements. The insert drawing is required for quotation.
Can GX control the pole position and field waveform of a multipole rotor?
The pole count, magnetization direction, circumferential pole position and agreed field waveform or magnetic response can be controlled against an approved pole map, measurement fixture, air gap and reference sample.
How are molding shrinkage, concentricity and rotor runout controlled?
Critical dimensions must reference a clear datum system. Tooling compensation, insert positioning, process control and sample measurements are then aligned with the bore, OD and working air-gap surfaces.
What temperature, moisture and chemical-exposure data are required?
Provide the continuous and peak temperatures, duty cycle, moisture or fluid exposure, relevant chemicals, storage conditions and required validation tests. These factors affect the magnetic compound, binder, insert interface and test plan.
How are insert retention and overspeed risks validated?
Define the rated speed, maximum or overspeed condition, torque load, temperature and acceptance criteria. GX can then evaluate a project-specific retention and mechanical validation plan before sample approval.
What should be included in a bonded magnet rotor RFQ?
Send 2D/3D drawings, the magnetic target, preferred material if known, pole map, insert or shaft drawing, critical datums and tolerances, operating speed and environment, sample quantity and estimated annual demand.
What is the typical lead time for custom bonded magnet rotor tooling and samples?
Tooling design and fabrication usually take 3 to 5 weeks, depending on the complexity of the mold and inserts. Initial samples are typically provided shortly after tooling completion for your evaluation and approval.
Do bonded magnet rotors require dynamic balancing?
It depends on the operating speed and application. While the molding process offers excellent uniformity, high-speed applications may still require dynamic balancing. We can incorporate balancing features into the mold design or perform post-molding balance correction if specified.
Request for quotation
Request a Quote for a Bonded Magnet Rotor
Include the rotor drawing, bonded material target, pole layout, insert or shaft interface, operating speed and environment, sample quantity and estimated annual demand.
- Rotor OD, bore, length, datums and critical molded dimensions
- Bonded ferrite or bonded NdFeB target and operating temperature
- Insert, shaft, sleeve or overmolded interface and retention features
- Pole map, field waveform, runout, speed and validation method