UMP 65x45 [M8]x2 GW F230+ Lina / N38 - search holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have stable power, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They show superior resistance to demagnetization from outside magnetic sources,
• Thanks to the shiny finish and nickel coating, they have an visually attractive appearance,
• The outer field strength of the magnet shows advanced magnetic properties,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• With the option for tailored forming and targeted design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Important function in new technology industries – they serve a purpose in hard drives, rotating machines, medical equipment along with technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They can break when subjected to a strong impact. If the magnets are exposed to mechanical hits, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and additionally increases its overall durability,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a damp environment – during outdoor use, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create precision features in the magnet – the use of a housing is recommended,
• Possible threat related to magnet particles may arise, in case of ingestion, which is crucial in the health of young users. Furthermore, small elements from these magnets can interfere with diagnostics after being swallowed,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Maximum holding power of the magnet – what contributes to it?

The given lifting capacity of the magnet means the maximum lifting force, calculated under optimal conditions, specifically:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Determinants of practical lifting force of a magnet

Practical lifting force is determined by factors, by priority:

• Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) can cause 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 performed on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under parallel forces the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.