UMH 25x8x45 [M5] / N38 - magnetic holder with hook

Pros as well as cons of NdFeB magnets.

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

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (based on calculations),
• They maintain their magnetic properties even under strong external field,
• Thanks to the elegant finish, the layer of nickel, gold, or silver-plated gives an visually attractive appearance,
• Magnetic induction on the surface of the magnet is very high,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of individual shaping and adjusting to concrete applications,
• Significant place in modern technologies – they are utilized in magnetic memories, electromotive mechanisms, precision medical tools, and modern systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of making threads in the magnet and complicated shapes - preferred is a housing - mounting mechanism.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. Furthermore, small components of these products can complicate diagnosis medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what it depends on?

The force parameter is a result of laboratory testing executed under the following configuration:

• using a base made of low-carbon steel, acting as a circuit closing element
• whose thickness reaches at least 10 mm
• with an polished touching surface
• under conditions of gap-free contact (metal-to-metal)
• during detachment in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Lifting capacity in real conditions – factors

In real-world applications, the actual lifting capacity is determined by a number of factors, listed from most significant:

• Distance – existence of any layer (paint, tape, air) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick sheet does not accept the full field, causing part of the flux to be escaped into the air.
• Metal type – not every steel attracts identically. Alloy additives worsen the attraction effect.
• Surface condition – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was measured by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the lifting capacity.