KM HF - 22 kg - magnetic bracket

Pros and cons of NdFeB magnets.

Besides their exceptional pulling force, neodymium magnets offer the following advantages:

• Their power is maintained, and after approximately 10 years it drops only by ~1% (according to research),
• They retain their magnetic properties even under external field action,
• By using a smooth layer of silver, the element gains an proper look,
• Magnets are characterized by huge magnetic induction on the outer side,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Thanks to freedom in forming and the ability to customize to complex applications,
• Versatile presence in innovative solutions – they are commonly used in hard drives, brushless drives, medical devices, as well as industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Problematic aspects of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• Neodymium magnets lose their force 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. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Limited ability of making threads in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Highest magnetic holding force – what it depends on?

Holding force of 22 kg is a result of laboratory testing executed under standard conditions:

• on a block made of mild steel, perfectly concentrating the magnetic field
• whose transverse dimension is min. 10 mm
• characterized by smoothness
• with zero gap (without coatings)
• for force applied at a right angle (pull-off, not shear)
• in neutral thermal conditions

Lifting capacity in real conditions – factors

It is worth knowing that the magnet holding may be lower influenced by the following factors, in order of importance:

• Space between surfaces – every millimeter of distance (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 sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Surface finish – ideal contact is obtained only on polished steel. Rough texture create air cushions, reducing force.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, in contrast under parallel forces the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.