UMT 11x17 colorless / N38 - board holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They retain their attractive force for almost 10 years – the loss is just ~1% (based on simulations),
• They are very resistant to demagnetization caused by external magnetic sources,
• By applying a shiny layer of silver, the element gains a modern look,
• The outer field strength of the magnet shows remarkable magnetic properties,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• With the option for tailored forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Wide application in advanced technical fields – they find application in hard drives, electric drives, clinical machines along with other advanced devices,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to external force, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks and additionally enhances its overall resistance,
• They lose magnetic force at high temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the dimensions and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to wet conditions can oxidize. Therefore, for outdoor applications, we recommend waterproof types made of coated materials,
• Limited ability to create internal holes in the magnet – the use of a housing is recommended,
• Health risk due to small fragments may arise, if ingested accidentally, which is notable in the health of young users. Furthermore, tiny components from these assemblies have the potential to hinder health screening after being swallowed,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Maximum lifting force for a neodymium magnet – what affects it?

The given strength of the magnet means the optimal strength, assessed in ideal conditions, that is:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• in conditions of no clearance
• under perpendicular detachment force
• under standard ambient temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice the following factors, from primary to secondary:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under parallel forces the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate decreases the lifting capacity.