MW 20x5 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets.

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

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (based on calculations),
• Magnets effectively resist against loss of magnetization caused by external fields,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Neodymium magnets deliver maximum magnetic induction on a small area, which allows for strong attraction,
• Neodymium magnets are characterized by extremely 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 detailed modeling and optimizing to individual applications,
• Universal use in innovative solutions – they are utilized in computer drives, brushless drives, medical equipment, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which makes them useful in compact constructions

Cons of neodymium magnets: tips and applications.

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a special holder, which not only secures them against impacts but also raises their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in realizing nuts and complicated shapes in magnets, we propose using cover - magnetic mechanism.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child safety. Additionally, small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

Best holding force of the magnet in ideal parameters – what affects it?

The declared magnet strength represents the maximum value, recorded under optimal environment, meaning:

• on a block made of structural steel, optimally conducting the magnetic field
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with a surface cleaned and smooth
• with direct contact (without impurities)
• for force acting at a right angle (in the magnet axis)
• in neutral thermal conditions

Determinants of lifting force in real conditions

Please note that the application force will differ influenced by elements below, in order of importance:

• Air gap (betwixt the magnet and the plate), since even a microscopic distance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Plate material – mild steel gives the best results. Higher carbon content decrease magnetic permeability and holding force.
• Plate texture – smooth surfaces ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, however under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the holding force.