MW 15x4 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Apart from their strong magnetism, neodymium magnets have these key benefits:

• They do not lose strength, even after nearly ten years – the drop in power is only ~1% (based on measurements),
• They maintain their magnetic properties even under external field action,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to look better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Possibility of accurate creating and adjusting to specific needs,
• Fundamental importance in advanced technology sectors – they are used in magnetic memories, electromotive mechanisms, diagnostic systems, as well as industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which makes them useful in miniature devices

Characteristics of disadvantages of neodymium magnets: tips and applications.

• At strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• Due to limitations in producing nuts and complex forms in magnets, we recommend using cover - magnetic holder.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these devices are able to be problematic in diagnostics medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Maximum holding power of the magnet – what contributes to it?

The force parameter is a result of laboratory testing executed under specific, ideal conditions:

• with the contact of a yoke made of special test steel, ensuring maximum field concentration
• possessing a thickness of min. 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of ideal adhesion (surface-to-surface)
• under perpendicular application of breakaway force (90-degree angle)
• in neutral thermal conditions

Magnet lifting force in use – key factors

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

• Distance (between the magnet and the metal), as even a tiny distance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to paint, rust or debris).
• Direction of force – maximum parameter is obtained only during perpendicular pulling. The shear force of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Surface finish – full contact is possible only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Thermal environment – temperature increase results in weakening of induction. Check the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.