MP 62x42x25 / N38 - ring magnet

Strengths and weaknesses of neodymium magnets.

Besides their exceptional magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over more than 10 years their performance decreases symbolically – ~1% (in testing),
• Neodymium magnets are characterized by extremely resistant to demagnetization caused by magnetic disturbances,
• A magnet with a metallic nickel surface looks better,
• The surface of neodymium magnets generates a maximum magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to versatility in designing and the ability to modify to individual projects,
• Fundamental importance in modern technologies – they are utilized in magnetic memories, motor assemblies, precision medical tools, also modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Drawbacks and weaknesses of neodymium magnets: tips and applications.

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of making threads in the magnet and complex shapes - preferred is cover - mounting mechanism.
• Potential hazard resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the context of child safety. Additionally, small elements of these products are able to be problematic in diagnostics medical after entering the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Maximum holding power of the magnet – what it depends on?

Information about lifting capacity was defined for the most favorable conditions, taking into account:

• on a base made of mild steel, perfectly concentrating the magnetic flux
• with a thickness minimum 10 mm
• with a plane free of scratches
• with total lack of distance (without coatings)
• during detachment in a direction perpendicular to the plane
• in stable room temperature

Lifting capacity in real conditions – factors

Holding efficiency is influenced by specific conditions, mainly (from priority):

• Distance (between the magnet and the plate), as even a tiny clearance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, rust or debris).
• Direction of force – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the plate is typically several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel attracts best. Alloy steels decrease magnetic permeability and lifting capacity.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases field saturation. Rough surfaces weaken the grip.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.