MW 55x25 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They do not lose power, even after nearly ten years – the decrease in power is only ~1% (according to tests),
• Neodymium magnets are distinguished by highly resistant to loss of magnetic properties caused by external magnetic fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to look better,
• Magnets have maximum magnetic induction on the working surface,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Considering the potential of free shaping and adaptation to custom solutions, magnetic components can be produced in a broad palette of geometric configurations, which makes them more universal,
• Universal use in high-tech industry – they are commonly used in hard drives, brushless drives, advanced medical instruments, as well as technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which allows their use in miniature devices

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited ability of making threads in the magnet and complex forms - preferred is cover - magnetic holder.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which gains importance in the context of child health protection. It is also worth noting that small components of these products are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what contributes to it?

The force parameter is a measurement result conducted under specific, ideal conditions:

• using a plate made of high-permeability steel, serving as a circuit closing element
• whose transverse dimension equals approx. 10 mm
• with a surface cleaned and smooth
• under conditions of gap-free contact (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

Please note that the working load may be lower depending on elements below, starting with the most relevant:

• Distance – the presence of foreign body (rust, tape, air) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Load vector – maximum parameter is available only during perpendicular pulling. The resistance to sliding of the magnet along the plate is usually several times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Material type – the best choice is pure iron steel. Hardened steels may attract less.
• Surface quality – the more even the surface, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal environment – temperature increase results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.