MW 20x5 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They possess excellent resistance to magnetism drop as a result of external fields,
• By using a decorative coating of gold, the element has an professional look,
• They are known for high magnetic induction at the operating surface, making them more effective,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to the possibility of precise forming and adaptation to individualized solutions, NdFeB magnets can be modeled in a variety of shapes and sizes, which expands the range of possible applications,
• Significant place in high-tech industry – they are commonly used in mass storage devices, electromotive mechanisms, advanced medical instruments, also technologically advanced constructions.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Due to limitations in creating threads and complex forms in magnets, we recommend using a housing - magnetic mount.
• Potential hazard resulting from small fragments of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. It is also worth noting that small elements of these magnets can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

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

The specified lifting capacity concerns the maximum value, obtained under optimal environment, specifically:

• on a plate made of mild steel, perfectly concentrating the magnetic field
• with a cross-section of at least 10 mm
• with an ideally smooth contact surface
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at standard ambient temperature

Practical aspects of lifting capacity – factors

During everyday use, the real power is determined by a number of factors, presented from the most important:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin sheet does not close the flux, causing part of the flux to be wasted into the air.
• Material type – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture create air cushions, reducing force.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was determined with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate decreases the load capacity.