MW 29x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of rare earth magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• Their magnetic field remains stable, and after approximately 10 years it drops only by ~1% (theoretically),
• Magnets perfectly defend themselves against loss of magnetization caused by foreign field sources,
• By covering with a decorative layer of silver, the element has an professional look,
• Magnetic induction on the working part of the magnet remains impressive,
• 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 ability of accurate molding and customization to unique solutions, neodymium magnets can be created in a broad palette of forms and dimensions, which amplifies use scope,
• Significant place in modern technologies – they are commonly used in hard drives, electric motors, medical devices, as well as other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They oxidize in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complicated shapes in magnets, we propose using cover - magnetic mount.
• Health risk to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small components of these magnets are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what affects it?

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

• using a plate made of high-permeability steel, serving as a ideal flux conductor
• whose transverse dimension reaches at least 10 mm
• characterized by smoothness
• with zero gap (without impurities)
• during pulling in a direction perpendicular to the mounting surface
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

Effective lifting capacity impacted by working environment parameters, such as (from priority):

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Steel grade – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Surface finish – full contact is obtained only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Temperature – heating the magnet results in weakening of force. Check the maximum operating temperature for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.