UMP 75x25 [M10x3] GW F200 GOLD Lina / N42 - search holder

Advantages as well as disadvantages of rare earth magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over more than ten years their performance decreases symbolically – ~1% (according to theory),
• They possess excellent resistance to magnetic field loss due to opposing magnetic fields,
• Thanks to the smooth finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an clean appearance,
• Magnetic induction on the surface of the magnet turns out to be very high,
• Due to their exceptional temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• Due to the ability of free molding and customization to unique projects, neodymium magnets can be modeled in a broad palette of geometric configurations, which amplifies use scope,
• Significant place in high-tech industry – they serve a role in mass storage devices, electric motors, precision medical tools, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose their strength 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
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in producing threads and complicated shapes in magnets, we recommend using a housing - magnetic holder.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Highest magnetic holding force – what contributes to it?

The lifting capacity listed is a measurement result performed under standard conditions:

• using a sheet made of mild steel, acting as a ideal flux conductor
• possessing a massiveness of min. 10 mm to ensure full flux closure
• with an ideally smooth contact surface
• with total lack of distance (no paint)
• during pulling in a direction vertical to the plane
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

In real-world applications, the actual holding force is determined by many variables, ranked from most significant:

• Distance (between the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Plate thickness – too thin plate causes magnetic saturation, causing part of the power to be lost to the other side.
• Steel grade – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.