Robotics & high-speed motors
Radial multi-pole rings for smooth, compact robot joints.
Mainrich manufactures sintered NdFeB radial rings, hollow-cup motor magnets, laminated assemblies, and rotor magnet sets for humanoid joints, cobots, servo motors, and high-speed BLDC programs. Evaluate each program by the real engineering variables: geometry, waveform, tolerance, and traceability.
Surface flux
+20-30%
vs tile assembly
Pole count
4-14
custom radial patterns
Flux variance
<1%
lot target
Field quality
Why radial multi-pole technology matters.
Standard radially oriented rings align grains in straight spokes, which can produce a saddle-shaped air-gap flux profile. Radial multi-pole rings use orientation tooling that curves the grain direction between poles, improving surface-flux utilization and waveform smoothness.
That difference is visible in the motor: less torque ripple, less audible noise, less vibration, and less correction work for the controller.
Curved grain orientation
The easy axis bends between poles instead of pointing in straight spokes, pushing useful flux toward the working air gap.
Sinusoidal surface field
A smoother waveform reduces cogging torque, vibration, and controller compensation work in humanoid and cobot joints.
Single-piece balance
No adhesive joints between arc magnets means fewer flux discontinuities and better mechanical balance at speed.
Air-gap flux density
Smooth waveform, lower harmonic content
B(theta)
Torque ripple
2-5%
radial target
Surface gain
+20-30%
design dependent
Inspection
100%
flux mapped
Architecture choice
Three magnet paths for different motor programs.
Robotics, EV auxiliary drives, and appliance motors do not need the same magnet architecture. The job is to match the ring geometry to torque smoothness, heat, cost, and production scale.
Best for robotics
Radial multi-pole rings
Single sintered rings with curved grain orientation. Use them when torque smoothness, actuator compactness, and repeatable flux mapping matter.
Best for high speed
Laminated assemblies
Thin insulated layers suppress eddy-current heating for high-RPM motors, drones, vacuums, and compact power-dense drives.
Best for flexible builds
Segmented ring assemblies
Arc segments bonded into a rotor ring. Useful when tooling flexibility, size range, or lower initial investment is the deciding factor.
Product range
Product range by motor decision.
Each row maps to the engineering decision buyers actually need: where it fits, how it is built, and what spec carries the risk.
Type
Radial multi-pole rings
Best fit
Humanoid joint servos, cobots, precision BLDC
Geometry
Single sintered ring, curved grain orientation
Key spec
+20-30% surface flux; 4-14 poles; sinusoidal waveform
Type
Coreless motor magnets
Best fit
Finger, wrist, small high-speed actuators
Geometry
Thin-wall hollow-cup ring, small bore control
Key spec
ID ±0.02 mm; concentricity ≤0.02 mm; pole angle control
Type
Laminated magnet assemblies
Best fit
High-RPM motors, EV auxiliary drives, drones
Geometry
Insulated magnet laminations bonded into a stack
Key spec
≥1 MΩ insulation; 0.05-0.2 mm insulation layer
Type
Segmented ring assemblies
Best fit
Scalable BLDC and selected robotics designs
Geometry
Matched arc segments with optional sleeve retention
Key spec
Post-assembly machining; straight or skew magnetization
QC stack
Dimensional and magnetic center control
Inner bore
±0.02 mm
Air-gap control
Concentricity
≤0.02 mm
Magnetic/mechanical center
Perpendicularity
≤0.03 mm
Stack alignment
Flux consistency
<1%
Controller predictability
Precision manufacturing
Tight geometry keeps the joint quiet.
Robotics applications are highly sensitive to air-gap variation. We control the mechanical center, magnetic center, bore fit, and surface flux together, because a good ring on a poor tolerance stack still creates actuator risk.
Incoming powder and grade confirmation
Orientation molding and sintering control
Grinding, bore control, and concentricity check
100% surface flux mapping with traceability
RFQ support
Building the next humanoid robot?
Share OD, ID, height, pole count, grade target, operating temperature, and expected monthly volume. We'll analyze radial multi-pole feasibility and the best backup architecture.