UMS 42x12.5x6.5x9 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They do not lose their magnetism, even after nearly ten years – the decrease of strength is only ~1% (based on measurements),
• They remain magnetized despite exposure to strong external fields,
• Because of the brilliant layer of silver, the component looks aesthetically refined,
• They have extremely strong magnetic induction on the surface of the magnet,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• The ability for accurate shaping and customization to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
• Wide application in modern technologies – they are used in hard drives, electric drives, clinical machines or even other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to physical collisions, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture and reinforces its overall resistance,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on shape). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Magnets exposed to damp air can corrode. Therefore, for outdoor applications, we suggest waterproof types made of non-metallic composites,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is restricted,
• Possible threat due to small fragments may arise, in case of ingestion, which is significant in the family environments. Furthermore, small elements from these magnets might hinder health screening after being swallowed,
• In cases of mass production, neodymium magnet cost may not be economically viable,

Breakaway strength of the magnet in ideal conditions – what affects it?

The given lifting capacity of the magnet means the maximum lifting force, determined in ideal conditions, specifically:

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a polished side
• in conditions of no clearance
• with vertical force applied
• at room temperature

What influences lifting capacity in practice

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.