MW 4x8 / N38 - cylindrical magnet

Pros and cons of NdFeB magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They do not lose power, even during nearly 10 years – the drop in strength is only ~1% (theoretically),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• Thanks to the smooth finish, the coating of nickel, gold, or silver gives an modern appearance,
• Neodymium magnets create maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Due to the potential of free shaping and customization to individualized projects, magnetic components can be produced in a variety of shapes and sizes, which increases their versatility,
• Huge importance in modern industrial fields – they are utilized in data components, brushless drives, precision medical tools, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a steel housing, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• They oxidize in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited possibility of creating nuts in the magnet and complex shapes - preferred is casing - magnetic holder.
• Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. It is also worth noting that small components of these devices can be problematic in diagnostics medical after entering the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Detachment force of the magnet in optimal conditions – what contributes to it?

The lifting capacity listed is a theoretical maximum value conducted under specific, ideal conditions:

• using a base made of high-permeability steel, serving as a ideal flux conductor
• with a cross-section no less than 10 mm
• with an polished contact surface
• with zero gap (no impurities)
• during pulling in a direction vertical to the plane
• at temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

Holding efficiency is influenced by working environment parameters, including (from priority):

• Space between magnet and steel – every millimeter of separation (caused e.g. by veneer or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Material type – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.