OD up to 300mm (11.8″), High-Power Generator Grade
We can offer large neodymium rings.
They come with outer diameters reaching up to 300mm (11.8 inches).
Producing magnets of this size requires special sintering and pressing equipment.
Most standard factories do not have them.
These big ring magnets are common for:
– High-torque industrial motors, magnetic separators, and medical imaging equipment (MRI/NMR).
– They require a massive, uniform magnetic field over a large surface area.
The “Saturation” Limit
Designing large magnets requires respecting the laws of physics.
Size matters, but Thickness matters more.
The “60mm Thickness” Rule:
We can manufacture rings with massive diameters (300mm).
Meanwhile, we recommend a Maximum Thickness of 60mm (2.36″) per single piece.
The Reason (Saturation):
Neodymium material must be energized by a magnetizing coil.
If a single block is thicker than 60mm, the magnetic pulse cannot fully penetrate to the core.
This results in a “soft” center and lower performance.
The Solution:
If your design requires a 100mm or 200mm tall ring, we will manufacture multiple 50mm rings and stack them.
This ensures every millimeter of the material is fully saturated and operating at peak power.
Manufacturing Capabilities
Dimensional Range:
Outer Diameter (OD): Custom up to 300mm.
Inner Diameter (ID): Fully customizable to fit your motor shaft or housing.
Thickness: Up to 60mm per piece (Stackable for greater height).
Tolerances:
Standard: ±0.1mm.
Large sintered blocks shrink during firing.
Holding ±0.05mm on a 300mm part is expensive and rarely necessary.
Machining:
We use large-format Inner/Outer Circle Grinding machines to ensure concentricity.
Material Grades:
N35 – N42:
The standard for large separators.
SH / UH Series:
Recommended for large Wind Turbine Generators or Industrial Motors to prevent demagnetization from heat.
Critical Safety & Handling Advisory
A 300mm Neodymium ring magnet can be dangerous to handle.
Such a strong rare earth magnet can generates thousands of pounds of pull force.
It can crush hands or shatter bones if handled improperly.
Our Packing:
We ship these rings with heavy wooden spacers and distinct separation.
Your Assembly:
You must use Mechanical Fixtures to install these.
Do not attempt to install a 300mm magnet by hand.
Ideal Applications
Green Energy: Rotors for Wind Turbines and Hydro-electric generators.
Medical Tech: Main field magnets for MRI and NMR spectroscopy devices.
Industrial Separation: Large rings used in mining chutes to pull tramp iron from ore.
Loudspeakers: Massive sub-woofer drivers for stadium audio systems.
Ordering Guide: Large Format Specs
To quote these accurately, please provide:
1). Dimensions: OD x ID x Thickness.
2). Assembly Plan: “Do you need these stacked? Will you be bolting them?” (We can machine countersunk holes if needed).
3). Coating:
– Nickel: Standard.
– Epoxy: Recommended for outdoor machinery (Wind Turbines).
– Zinc: Good for large adhesive bonding surfaces.
4). Magnetization:
– Axial: (Top/Bottom faces are poles). Most common for stacks.
– Diametric: (Curved sides are poles). Rare for rings this size, but possible.
Packing Method
It is important to guarantee safe transit for big NdFeB magnets.
And comply with international IATA and IMDG regulations.
We follow a 3-stage shielding method for all large neodymium shipments.
1). First, we put the magnets in dense foam to create a protective air gap.
2). Then, line the shipping cartons with steel plates to securely contain the intense magnetic flux.
- When shipping multiple pieces, we will alternate pole alignments.
- Neutralize stray magnetic fields.
- Insert sturdy spacers between the magnets.
This way, we can ensure safe, pinch-free separation upon unpacking.
3). Finally, every package will undergo stringent field-strength testing before sending to shippers.
Follow these 3 essential steps, we can guarantee such big strong magnets pass airline safety standards.
And assure a secure and hassle-free delivery to you.
