MW 15x4 / N38 - cylindrical magnet

Pros and cons of neodymium magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• Their magnetic field is maintained, and after around ten years it decreases only by ~1% (according to research),
• They maintain their magnetic properties even under external field action,
• A magnet with a smooth silver surface looks better,
• They show high magnetic induction at the operating surface, which increases their power,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Possibility of individual shaping and adapting to defined conditions,
• Universal use in electronics industry – they are used in hard drives, drive modules, precision medical tools, also industrial machines.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• To avoid cracks under impact, we suggest using special steel housings. Such a solution protects 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.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Health risk resulting from small fragments of magnets are risky, if swallowed, which becomes key in the context of child safety. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum lifting force for a neodymium magnet – what contributes to it?

The declared magnet strength refers to the maximum value, obtained under ideal test conditions, namely:

• on a plate made of structural steel, optimally conducting the magnetic field
• with a thickness of at least 10 mm
• with a surface perfectly flat
• with direct contact (without paint)
• during detachment in a direction perpendicular to the plane
• at room temperature

Practical aspects of lifting capacity – factors

In real-world applications, the actual holding force is determined by a number of factors, presented from the most important:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – highest force is available only during perpendicular pulling. The shear force of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – insufficiently thick sheet does not accept the full field, causing part of the power to be wasted into the air.
• Metal type – not every steel reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Thermal factor – hot environment reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.