Custom Big Sintered Neodymium Disc Magnets

Diameters up to 300mm – Industrial Separation & Motor Grade, Heavy-Duty Holding

We can offer large NdFeB discs as per your specific diameter and thickness.

Standard magnets are measured in millimeters.
Our industrial disc magnets are measured in centimeters.
We can sinter and grind single-piece discs with diameters up to 300mm (11.8 inches).

These massive magnets are the “engines” behind industrial magnetic separators, wind turbine rotors, and MRI equipment.
They can generate deep, penetrating magnetic fields.

• Capable of pulling heavy ferrous metal from a distance.
• Or, generating massive torque in low-speed generators.

Designing at Scale

Big magnets behave differently than small ones.

Here is the physics:

The Saturation Limit (Thickness Rule):

The Constraint:
To magnetize a large disc, we must penetrate the core with a massive magnetic pulse.

The Limit:
For a single solid disc, we recommend a Maximum Thickness of 60mm.

The Solution:
If you need a disc thicker than 60mm (e.g., a 100mm cylinder), they are possible in a different way.

• We can make multiple thinner discs (e.g., 2 x 50mm) and stack/bond them.
• This ensures the magnet is fully saturated and operating at 100% efficiency.

Mounting Strategy (Bolting vs. Gluing):

The Problem:
A 100mm disc can generate 300kg of pull force.
Industrial glues often fail under this load, causing the magnet to rip loose.

The Solution:
For discs this large, we strongly recommend Mechanical Fastening.
We can machine a Central Countersunk Hole or a Counterbore.
They allow you to bolt the magnet securely to your assembly using a non-magnetic steel screw.

Edge Protection:

The Risk:
Large discs are heavy.
If they tip over or snap to a steel plate, the edges will chip.

Our Standard:
We apply a Heavy Chamfer (Beveled Edge) to all large discs.
This protects the brittle sintered material from impact damage during handling and installation.

Critical Safety Advisory

A 150mm N52 Disc is a dangerous piece of industrial machinery.

The “Crush” Hazard:

The Danger:
These magnets will attract steel from 30cm away.
If a hand is caught between the magnet and a steel wall, it will result in crushed bones.

Handling:
Never handle these manually.
Use Wooden Jigs or non-magnetic tools.

Separation Method:

The Packing:
We ship these discs with Thick Wooden Spacers (20mm+) between them.

The Unpacking:
You cannot pull them apart.
You must slide them apart using a mechanical lever or the edge of a workbench.

Ideal Applications

• Magnetic Separators: Suspended discs over conveyor belts to remove tramp iron.
• Wind Power: Axial flux generator rotors (Pancake motors).
• Salvage & Retrieval: “Magnet Fishing” for heavy underwater scrap.
• Sputtering Targets: Large planar cathodes for vacuum coating.
• MRI / NMR: Homogeneous field generation for medical imaging.

Ordering Guide: Large Format Specs

To prevent costly manufacturing errors, please specify:

1). Dimensions: Diameter x Thickness.

2). Mounting:

• Solid Disc: (For gluing/clamping).
• Bolt-Hole: “Do you need a central countersunk hole for an M8/M10 bolt?”

3). Application: “Is this for a Motor (High Heat) or a Separator (Room Temp)?”

• If Motor: We may suggest SH/UH grades.

Safety Packing:
Do you have the equipment to handle a 50kg magnet?
We can crate them individually if needed.

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.