About Ring Magnets
Plain NdFeB rings — axially or diametrically magnetized with a single pole pair — are the workhorse magnet form for voice coil motors, loudspeaker assemblies, magnetic couplings, holding fixtures, and sensor systems. Distinct from radial multi-pole rings, which have multiple poles around the circumference, plain rings are single-pole-pair magnets used where uniform axial or diametric flux is required.
Production Capability
- •OD range: 3mm to 400mm
- •Wall thickness: 0.5mm minimum
- •Axial length: 1mm to 150mm
- •Axial or diametric magnetization
- •Dimensional tolerance to ±0.02mm on critical surfaces
- •Full grade range with GBD processing for high-temp applications
Typical Use Cases
- •Voice coil motors (VCM)
- •Loudspeaker drivers
- •Magnetic couplings (torque transmission through non-contact interface)
- •Holding magnets and fixtures
- •Hall-effect sensor pair magnets
- •Small electric motor assemblies
Typical Dimensions & Tolerances
Dimensions
OD 3–400mm, ID 1mm min, axial length 1–150mm
Tolerances
±0.02mm on critical dimensions, perpendicularity ≤0.05mm
Recommended Grades for Ring
N38
80°CCost-efficient mid-range sintered NdFeB for general permanent-magnet assemblies up to 80°C.
N42
80°CHigh-performance sintered NdFeB grade widely used in compact motors, generators, and precision actuators.
N45
80°CHigher-flux sintered NdFeB grade suited to compact, high-torque designs where temperature is controlled.
N42H
120°CWorkhorse high-temperature NdFeB grade for automotive motors, pumps, and industrial drives up to 120°C.
N45H
120°CHigher-flux H-series NdFeB grade for compact 120°C motor designs demanding both torque and thermal stability.
Related Applications
Industrial Automation
NdFeB magnets for stepper motors, servo drives, linear actuators, magnetic couplings, and factory automation equipment across European and North American manufacturing.
Medical Devices
Precision NdFeB magnets for MRI equipment, surgical robotics, implantable devices, dental applications, and medical sensors — with the biocompatibility and traceability medical programs require.
Frequently Asked Questions
What is the difference between axial and diametric magnetization on a ring magnet?
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Axial magnetization produces a magnetic field parallel to the ring's axis (through the hole), with north on one flat face and south on the opposite. Diametric magnetization produces a field perpendicular to the axis, with north on one side of the circumference and south on the opposite side. The choice depends on the application: voice coil motors use axial, sensor applications typically use diametric, magnetic couplings can use either depending on the torque transfer geometry.
What is the smallest ring magnet you can produce?
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Our standard minimum outer diameter is 3mm with 1mm minimum inner diameter. Below this, custom tooling is required and economics favor alternative materials or form factors. For precision applications requiring very small magnets, miniature rings in the 3–10mm OD range are a routine production configuration.
Request a Quote for Ring Magnets
Share dimensions, quantity, grade, and target application. Our engineering team responds within 1 business day with grade recommendation, followed by pricing and lead time within 2 business days.