NCM 40x13.5x5 / N38 - channel magnetic holder

Advantages and disadvantages of NdFeB magnets.

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

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They maintain their magnetic properties even under strong external field,
• A magnet with a metallic gold surface has better aesthetics,
• They feature 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...
• Due to the option of precise molding and adaptation to custom solutions, neodymium magnets can be created in a broad palette of forms and dimensions, which amplifies use scope,
• Significant place in advanced technology sectors – they are commonly used in HDD drives, brushless drives, medical equipment, and technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited ability of making nuts in the magnet and complicated shapes - recommended is cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these products can disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Optimal lifting capacity of a neodymium magnet – what it depends on?

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

• using a base made of mild steel, acting as a magnetic yoke
• with a cross-section of at least 10 mm
• characterized by even structure
• without the slightest clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

Real force impacted by specific conditions, including (from most important):

• Gap between magnet and steel – every millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Direction of force – highest force is reached only during perpendicular pulling. The force required to slide of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin plate does not accept the full field, causing part of the flux to be lost into the air.
• Steel grade – ideal substrate is high-permeability steel. Stainless steels may have worse magnetic properties.
• Surface condition – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Thermal conditions – neodymium magnets 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).

* Lifting capacity was determined by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, in contrast under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a minimal clearance {between} the magnet and the plate reduces the load capacity.