AM lina fi 10 mm - magnetic accessories

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their tremendous magnetic power, neodymium magnets offer the following advantages:

• They retain their magnetic properties for almost 10 years – the drop is just ~1% (in theory),
• Their ability to resist magnetic interference from external fields is notable,
• By applying a reflective layer of silver, the element gains a modern look,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• Thanks to their high temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• Thanks to the flexibility in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in diverse shapes and sizes, which increases their usage potential,
• Wide application in modern technologies – they find application in data storage devices, electric motors, clinical machines as well as other advanced devices,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, with minimal size,

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to physical collisions, they should be placed in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture while also enhances its overall durability,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent decline in performance (depending on size). 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,
• They rust in a moist environment. If exposed to rain, we recommend using sealed magnets, such as those made of rubber,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is difficult,
• Safety concern from tiny pieces may arise, especially if swallowed, which is notable in the family environments. It should also be noted that tiny components from these magnets can interfere with diagnostics once in the system,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

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

The given holding capacity of the magnet corresponds to the highest holding force, calculated under optimal conditions, specifically:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• with vertical force applied
• under standard ambient temperature

Determinants of lifting force in real conditions

The lifting capacity of a magnet is determined by in practice the following factors, from primary to secondary:

• Air gap between the magnet and the plate, because 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 was measured using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate lowers the load capacity.