AM ucho [M12] - magnetic accessories

Strengths and weaknesses of rare earth magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• Their strength is durable, and after around 10 years it drops only by ~1% (according to research),
• Neodymium magnets are distinguished by exceptionally resistant to loss of magnetic properties caused by magnetic disturbances,
• Thanks to the shiny finish, the coating of nickel, gold, or silver-plated gives an clean appearance,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Possibility of individual creating and adjusting to concrete conditions,
• Huge importance in electronics industry – they are utilized in magnetic memories, drive modules, medical devices, as well as multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets lose their power 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
• 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 and corrosion.
• Due to limitations in creating nuts and complex shapes in magnets, we propose using a housing - magnetic mechanism.
• Potential hazard to health – tiny shards of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small components of these magnets can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

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

The lifting capacity listed is a theoretical maximum value conducted under specific, ideal conditions:

• with the use of a yoke made of low-carbon steel, ensuring full magnetic saturation
• whose transverse dimension reaches at least 10 mm
• with an ideally smooth touching surface
• under conditions of ideal adhesion (metal-to-metal)
• under perpendicular application of breakaway force (90-degree angle)
• at room temperature

Determinants of practical lifting force of a magnet

Please note that the application force may be lower influenced by the following factors, starting with the most relevant:

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – too thin steel does not accept the full field, causing part of the power to be wasted into the air.
• Steel grade – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
• Plate texture – smooth surfaces ensure maximum contact, which improves force. Uneven metal reduce efficiency.
• Thermal environment – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the lifting capacity.