MW 40x15 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They retain attractive force for nearly 10 years – the drop is just ~1% (according to analyses),
• They possess excellent resistance to magnetic field loss due to external magnetic sources,
• By using a decorative layer of nickel, the element presents an aesthetic look,
• Magnets possess huge magnetic induction on the surface,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of custom modeling as well as adjusting to precise requirements,
• Universal use in high-tech industry – they are utilized in hard drives, drive modules, medical devices, as well as industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• We suggest cover - magnetic mount, due to difficulties in producing nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the context of child health protection. It is also worth noting that small components of these products are able to be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is a challenge,

Maximum magnetic pulling force – what it depends on?

The specified lifting capacity represents the maximum value, recorded under optimal environment, namely:

• with the application of a sheet made of low-carbon steel, ensuring maximum field concentration
• with a thickness minimum 10 mm
• with a surface cleaned and smooth
• without any air gap between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at room temperature

Determinants of lifting force in real conditions

Effective lifting capacity is affected by working environment parameters, such as (from most important):

• Gap (betwixt the magnet and the metal), because even a very small distance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin sheet does not close the flux, causing part of the flux to be lost into the air.
• Metal type – not every steel attracts identically. Alloy additives weaken the attraction effect.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate decreases the lifting capacity.