MP 5x2.7/1.2x5 C / N38 - ring magnet

Pros and cons of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (according to literature),
• They feature excellent resistance to magnetic field loss when exposed to external magnetic sources,
• Thanks to the shimmering finish, the plating of nickel, gold, or silver gives an clean appearance,
• They show high magnetic induction at the operating surface, which increases their power,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of precise forming and adapting to complex applications,
• Wide application in high-tech industry – they are used in HDD drives, electromotive mechanisms, diagnostic systems, and industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

What to avoid - cons of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic holder, due to difficulties in producing threads inside the magnet and complex forms.
• Possible danger to health – tiny shards of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small components of these devices can disrupt the diagnostic process medical when they are in the body.
• Due to complex production process, their price is higher than average,

Highest magnetic holding force – what affects it?

Breakaway force was determined for optimal configuration, taking into account:

• on a block made of structural steel, effectively closing the magnetic field
• with a cross-section minimum 10 mm
• with a surface free of scratches
• with total lack of distance (no coatings)
• for force acting at a right angle (in the magnet axis)
• at standard ambient temperature

Lifting capacity in real conditions – factors

Holding efficiency is affected by working environment parameters, including (from most important):

• Gap (between the magnet and the plate), since even a microscopic clearance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick plate does not accept the full field, causing part of the flux to be wasted into the air.
• Material composition – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Smoothness – full contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.