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

Strengths as well as weaknesses of NdFeB magnets.

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

• They do not lose strength, even during nearly ten years – the decrease in power is only ~1% (based on measurements),
• Neodymium magnets are exceptionally resistant to magnetic field loss caused by external field sources,
• In other words, due to the aesthetic layer of silver, the element gains a professional look,
• Magnetic induction on the top side of the magnet remains strong,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of custom creating and optimizing to atypical conditions,
• Key role in electronics industry – they are used in data components, electric motors, medical equipment, also complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic holder, due to difficulties in producing nuts inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these devices can complicate diagnosis medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

Magnetic strength at its maximum – what it depends on?

Breakaway force was determined for the most favorable conditions, assuming:

• on a base made of structural steel, optimally conducting the magnetic flux
• whose thickness is min. 10 mm
• with a surface free of scratches
• with zero gap (no paint)
• for force applied at a right angle (pull-off, not shear)
• in neutral thermal conditions

Practical lifting capacity: influencing factors

In practice, the actual holding force results from a number of factors, ranked from most significant:

• Distance – existence of any layer (rust, dirt, gap) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick plate does not accept the full field, causing part of the flux to be wasted to the other side.
• Metal type – not every steel reacts the same. Alloy additives worsen the attraction effect.
• Smoothness – full contact is possible only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.