UMH 32x8x46 [M6] / N38 - magnetic holder with hook

Pros and cons of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They retain full power for nearly 10 years – the drop is just ~1% (based on simulations),
• Neodymium magnets are characterized by extremely resistant to magnetic field loss caused by external field sources,
• Thanks to the reflective finish, the layer of Ni-Cu-Ni, gold, or silver gives an visually attractive appearance,
• Neodymium magnets deliver maximum magnetic induction on a small surface, which allows for strong attraction,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Considering the potential of flexible molding and adaptation to individualized solutions, NdFeB magnets can be modeled in a variety of geometric configurations, which expands the range of possible applications,
• Key role in advanced technology sectors – they are commonly used in mass storage devices, brushless drives, advanced medical instruments, as well as industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose their power 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 stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of creating nuts in the magnet and complicated shapes - preferred is casing - mounting mechanism.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which is particularly important in the context of child health protection. Additionally, small components of these magnets can be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price is higher than average,

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

The load parameter shown refers to the limit force, measured under optimal environment, specifically:

• with the application of a sheet made of special test steel, guaranteeing maximum field concentration
• whose thickness equals approx. 10 mm
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• during pulling in a direction perpendicular to the plane
• in stable room temperature

What influences lifting capacity in practice

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

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal weaken the grip.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the holding force.