MW 8x1.5 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

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

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
• They maintain their magnetic properties even under close interference source,
• In other words, due to the shiny layer of silver, the element gains visual value,
• They show high magnetic induction at the operating surface, which increases their power,
• 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...
• Due to the option of accurate molding and adaptation to unique requirements, magnetic components can be manufactured in a variety of geometric configurations, which makes them more universal,
• Versatile presence in modern technologies – they are commonly used in hard drives, drive modules, precision medical tools, and technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Cons of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• They rust in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is a housing - magnet mounting.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that tiny parts of these magnets are able to disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The specified lifting capacity refers to the peak performance, recorded under ideal test conditions, namely:

• on a block made of structural steel, optimally conducting the magnetic field
• with a thickness of at least 10 mm
• with a plane free of scratches
• without any insulating layer between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at standard ambient temperature

Determinants of lifting force in real conditions

Holding efficiency is affected by working environment parameters, mainly (from priority):

• Gap 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 obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Alloy admixtures decrease magnetic properties and holding force.
• Surface finish – full contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Thermal factor – hot environment weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.