UMH 20x7x35 [M4] / N38 - magnetic holder with hook

Pros and cons of neodymium magnets.

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

• They retain attractive force for nearly 10 years – the loss is just ~1% (in theory),
• They possess excellent resistance to magnetism drop when exposed to external fields,
• Thanks to the shimmering finish, the surface of Ni-Cu-Ni, gold, or silver-plated gives an modern appearance,
• Neodymium magnets ensure maximum magnetic induction on a contact point, which ensures high operational effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to freedom in forming and the ability to modify to complex applications,
• Wide application in high-tech industry – they are commonly used in computer drives, motor assemblies, diagnostic systems, and technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a special holder, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest cover - magnetic mount, due to difficulties in creating nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these products can be problematic in diagnostics medical when they are in the body.
• Due to expensive raw materials, their price is relatively high,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

Holding force of 14.5 kg is a result of laboratory testing executed under specific, ideal conditions:

• using a plate made of mild steel, functioning as a circuit closing element
• whose thickness is min. 10 mm
• with an polished contact surface
• with zero gap (without impurities)
• during pulling in a direction vertical to the mounting surface
• at temperature room level

Practical aspects of lifting capacity – factors

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

• Clearance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the load capacity.