Which magnet should I choose?

For many applications, choosing a magnet seems simple. Yet, there are hundreds of different shapes, sizes, coatings, and magnet grades. What works perfectly for one application can be completely unsuitable for another situation.

Therefore, choosing the right magnet starts not with the magnet itself, but with the application.

There is no universally best magnet

A common misconception is that the strongest magnet is automatically the best choice.

In reality, several factors play a role:

• required holding force
• available space
• temperature
• humidity
• mounting method
• safety
• aesthetics

A small N52 magnet is not automatically better than a larger N35 magnet.

Ultimately, the application determines which solution is most suitable.

Step 1: Determine the purpose

The first question is always:

What should the magnet do?

Possible applications include:

• fastening
• positioning
• closing
• separating
• detecting
• driving

A magnetic latch for a cupboard door has different requirements than a magnet in an industrial machine.

Step 2: How much force is needed?

Holding force is often the first thing users look at.

However, a distinction must be made between:

• pulling force
• shear force

A magnet that theoretically has a holding force of 20 kg will often be able to hold significantly less weight in a vertical application.

Therefore, it is always wise to maintain a safety margin.

Step 3: Indoors or outdoors?

The environment plays an important role.

For dry indoor environments, a standard nickel-plated neodymium magnet is usually sufficient.

For applications in damp areas or outdoor environments, coatings such as epoxy or plastic deserve extra attention.

Step 4: Temperature

When a magnet is exposed to heat, it can affect its performance.

For standard neodymium magnets, a maximum operating temperature of approximately 80°C often applies.

For higher temperatures, special grades may be required.

Step 5: Magnet shape

Not every shape delivers the same performance.

Common shapes include:

Disc Magnets

Compact and versatile.

Block Magnets

Large contact surface and high holding force.

Ring Magnets

Suitable for shafts, bolts, and technical applications.

Bar Magnets

Often used for demonstrations, sensors, and specific technical applications.

Pot Magnets

Maximum holding force in a compact design.

Step 6: Magnet grade

For neodymium magnets, grades used include:

• N35
• N42
• N48
• N52

A higher grade means more magnetic energy within the same volume.

However, this is only one of the factors that determine performance.

Step 7: Coating

The coating largely determines the durability of the magnet.

Common finishes include:

• Ni-Cu-Ni
• epoxy
• rubber
• plastic
• gold
• rose gold
• gunmetal

The choice depends on the environment and the desired aesthetic.

When is neodymium the right choice?

For most applications where maximum strength is desired, neodymium is the best choice.

Neodymium magnets combine:

• high holding force
• compact dimensions
• long lifespan
• excellent performance

As a result, they have become the most commonly used powerful permanent magnets in the world.

Conclusion

Choosing the right magnet starts with the application. Factors such as holding force, dimensions, temperature, coating, and mounting are often more important than just the magnet grade. By carefully considering the conditions beforehand, a magnet can be selected that performs optimally and remains reliable for years to come.