FM Ruszt magnetyczny do leja fi 200 dwupoziomowy / N52 - magnetic filter

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their magnetic properties for nearly ten years – the loss is just ~1% (in theory),
• They protect against demagnetization induced by ambient electromagnetic environments effectively,
• Thanks to the glossy finish and silver coating, they have an visually attractive appearance,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• With the option for customized forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Wide application in new technology industries – they find application in data storage devices, rotating machines, diagnostic apparatus and technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to shocks, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall strength,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on form). 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 wet environment – during outdoor use, we recommend using sealed magnets, such as those made of plastic,
• Limited ability to create internal holes in the magnet – the use of a magnetic holder is recommended,
• Potential hazard linked to microscopic shards may arise, especially if swallowed, which is important in the context of child safety. Furthermore, miniature parts from these products can complicate medical imaging after being swallowed,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Highest magnetic holding force – what affects it?

The given strength of the magnet means the optimal strength, measured under optimal conditions, namely:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• under standard ambient temperature

Determinants of lifting force in real conditions

In practice, the holding capacity of a magnet is affected by the following aspects, in descending order of importance:

• Air gap between the magnet and the plate, since 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.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.