MP 5x2.7/1.2x5 S / N38 - ring magnet

Strengths as well as weaknesses of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They do not lose their magnetic properties even under strong external field,
• A magnet with a shiny nickel surface is more attractive,
• They feature high magnetic induction at the operating surface, making them more effective,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of custom modeling and optimizing to defined conditions,
• Key role in high-tech industry – they are utilized in magnetic memories, electric drive systems, advanced medical instruments, and other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in creating nuts and complicated shapes in magnets, we recommend using casing - magnetic holder.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these products can disrupt the diagnostic process medical after entering the body.
• With large orders the cost of neodymium magnets can be a barrier,

Magnetic strength at its maximum – what affects it?

Breakaway force is the result of a measurement for optimal configuration, assuming:

• on a block made of structural steel, perfectly concentrating the magnetic flux
• whose transverse dimension is min. 10 mm
• with an ideally smooth contact surface
• with zero gap (no impurities)
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature room level

Lifting capacity in practice – influencing factors

Real force is influenced by specific conditions, including (from priority):

• Clearance – existence of any layer (rust, tape, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Base massiveness – insufficiently thick plate does not accept the full field, causing part of the flux to be escaped into the air.
• Steel grade – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Base smoothness – the more even the surface, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, whereas under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.