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

Strengths and weaknesses of rare earth magnets.

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

• Their power remains stable, and after around ten years it decreases only by ~1% (according to research),
• Magnets perfectly defend themselves against demagnetization caused by ambient magnetic noise,
• The use of an shiny finish of noble metals (nickel, gold, silver) causes the element to look better,
• Magnets are characterized by huge magnetic induction on the active area,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Possibility of individual shaping as well as optimizing to concrete applications,
• Wide application in electronics industry – they are used in mass storage devices, electric motors, precision medical tools, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• We suggest casing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex forms.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child health protection. Additionally, small elements of these products can be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Highest magnetic holding force – what affects it?

The load parameter shown represents the limit force, recorded under optimal environment, meaning:

• with the application of a yoke made of low-carbon steel, ensuring full magnetic saturation
• whose thickness reaches at least 10 mm
• with an polished touching surface
• with zero gap (no coatings)
• under perpendicular force direction (90-degree angle)
• at ambient temperature room level

Lifting capacity in practice – influencing factors

Real force is affected by working environment parameters, including (from priority):

• Distance (between the magnet and the metal), since even a tiny distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Cast iron may attract less.
• Surface finish – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.