JM 15x40 - jajka w pudełku/cena za parę - magnetic eggs

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their consistent holding force, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after ten years, the performance loss is only ~1% (according to literature),
• They remain magnetized despite exposure to strong external fields,
• In other words, due to the shiny nickel coating, the magnet obtains an aesthetic appearance,
• Magnetic induction on the surface of these magnets is notably high,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• With the option for customized forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Key role in new technology industries – they find application in computer drives, electric drives, healthcare devices as well as other advanced devices,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time increases its overall resistance,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to humidity can rust. Therefore, for outdoor applications, it's best to use waterproof types made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing complex structures directly in the magnet,
• Potential hazard due to small fragments may arise, if ingested accidentally, which is important in the health of young users. It should also be noted that small elements from these assemblies can interfere with diagnostics when ingested,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

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

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

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Key elements affecting lifting force

The lifting capacity of a magnet is determined by 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) 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 conducted on a smooth plate of optimal thickness, under perpendicular forces, whereas under parallel forces the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.