SMZR 32x200 / N52 - magnetic separator with handle

Advantages and disadvantages of neodymium magnets.

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

• Their magnetic field is durable, and after approximately 10 years it decreases only by ~1% (theoretically),
• Neodymium magnets are characterized by extremely resistant to magnetic field loss caused by magnetic disturbances,
• In other words, due to the aesthetic finish of silver, the element gains visual value,
• They feature high magnetic induction at the operating surface, making them more effective,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of custom creating as well as modifying to individual applications,
• Key role in future technologies – they serve a role in hard drives, electric drive systems, medical equipment, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• 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 stability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• We recommend a housing - magnetic mount, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Possible danger resulting from small fragments of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. Additionally, small elements of these devices are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum magnetic pulling force – what contributes to it?

Breakaway force was determined for the most favorable conditions, taking into account:

• with the application of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a thickness of min. 10 mm to avoid saturation
• with a surface cleaned and smooth
• under conditions of ideal adhesion (surface-to-surface)
• during pulling in a direction vertical to the mounting surface
• at temperature room level

Practical aspects of lifting capacity – factors

Real force impacted by specific conditions, including (from priority):

• Gap between magnet and steel – every millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be wasted into the air.
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may attract less.
• Plate texture – ground elements ensure maximum contact, which increases force. Rough surfaces reduce efficiency.
• Thermal factor – hot environment weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.