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How Rare Earth Magnets are Made

The unparalleled strength of neodymium magnets is only possible due to a sophisticated and delicate arrangement of atomic particles and their electron spin. The process to produce these technological marvels is no less sophisticated or delicate.

The manufacturing process for rare earth magnets in general, and neodymium magnets in particular is strictly licensed. Recently some of the most restrictive patents have begun to expire which has helped spur the growth of the market and the availability of neodymium magnets. However, Sumitomo Special Metals (now NEOMAX) still holds many patents that must be licensed by approved manufacturers.

Mining

Even though they are called "rare earth" or "neodymium" magnets, they contain a lot iron and other metals. All of the neodymium, iron, samarium, cobalt, nickel, etc comes from the ground.

Grinding and Mixing the Alloy

Once the raw material is available, it must be ground to a powder and mixed to create the various grades of materials. Different mixtures will create materials with various magnetic properties. Some are stronger, others more durable, and others can last longer in high temperatures.

machines used to mix ndfeb rare earth magnet materials

Pressing

The next step is to press the mixture together into a form.

Particle Alignment

We use a large electromagnet to optimize the pressed mixture for magnetization.

Sintering

Once the particles are aligned, we can sinter the material to firmly lock everything in place.

sintering unit for manufacturing neodymium magnets

Milling and Cutting

The material can be further refined by cutting and machining to smaller pieces. Tolerances are usually +/- 0.05mm. Micro machining specialists can work with much higher tolerances.

Milling equipment for manufacturing neodymium magnets

Plating / Coating

After the final shape of the magnet is finished, we must coat or plate each piece to protect from corrosion. This is especially true for Neodymium Iron Boron magnets which are very susceptible to corrosion. Normal platings include Nickel, Nickle + Copper + Nickel, Epoxy Coating, Gold, ABS Plastic, and Zinc.

Magnetization

Magnetization happens after all of the machining and plating. Neodymium magnets can only be magnetized in the direction they were setup for in the alignment phase.

Each magnet is inspected and sampled for quality assurance tests.

magnet testing facilities for manufacturing neodymium magnets