MW 15x4 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• They retain full power for around 10 years – the drop is just ~1% (based on simulations),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• In other words, due to the aesthetic surface of nickel, the element gains visual value,
• Neodymium magnets generate maximum magnetic induction on a small area, which allows for strong attraction,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to the option of flexible shaping and customization to unique requirements, magnetic components can be produced in a wide range of shapes and sizes, which expands the range of possible applications,
• Universal use in modern technologies – they are utilized in HDD drives, electric motors, medical devices, as well as technologically advanced constructions.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Problematic aspects of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets can be dangerous, if swallowed, which is particularly important in the context of child safety. It is also worth noting that small components of these magnets are able to disrupt the diagnostic process medical after entering the body.
• Due to complex production process, their price is higher than average,

Detachment force of the magnet in optimal conditions – what affects it?

Holding force of 3.32 kg is a result of laboratory testing executed under specific, ideal conditions:

• on a block made of mild steel, effectively closing the magnetic field
• whose thickness reaches at least 10 mm
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Lifting capacity in practice – influencing factors

During everyday use, the real power is determined by a number of factors, listed from the most important:

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is reached only during perpendicular pulling. The force required to slide of the magnet along the surface is usually several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material type – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Rough surfaces weaken the grip.
• Temperature – temperature increase results in weakening of induction. Check the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate reduces the holding force.