MW 15x10 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• They have excellent resistance to weakening of magnetic properties when exposed to external magnetic sources,
• Thanks to the shimmering finish, the plating of Ni-Cu-Ni, gold-plated, or silver gives an modern appearance,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of detailed creating as well as adapting to atypical needs,
• Key role in modern industrial fields – they are utilized in HDD drives, electric motors, medical equipment, as well as industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in compact constructions

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in force. 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
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complex forms in magnets, we recommend using a housing - magnetic mechanism.
• Possible danger resulting from small fragments of magnets are risky, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, small components of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• Due to neodymium price, their price is higher than average,

Optimal lifting capacity of a neodymium magnet – what affects it?

Information about lifting capacity was defined for optimal configuration, including:

• using a plate made of mild steel, functioning as a magnetic yoke
• possessing a thickness of minimum 10 mm to avoid saturation
• with an ideally smooth touching surface
• under conditions of ideal adhesion (metal-to-metal)
• under vertical force direction (90-degree angle)
• in stable room temperature

Practical lifting capacity: influencing factors

Holding efficiency is affected by working environment parameters, such as (from priority):

• Clearance – the presence of any layer (paint, tape, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is usually several times smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin sheet does not accept the full field, causing part of the flux to be escaped to the other side.
• Material type – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Temperature – temperature increase causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, whereas under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.