UMH 60x15x69 [M8] / N38 - magnetic holder with hook

Strengths and weaknesses of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• Their magnetic field is maintained, and after approximately ten years it drops only by ~1% (according to research),
• Neodymium magnets remain extremely resistant to demagnetization caused by external field sources,
• A magnet with a smooth nickel surface is more attractive,
• Magnetic induction on the working part of the magnet is exceptional,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• In view of the possibility of precise forming and adaptation to unique projects, magnetic components can be created in a variety of geometric configurations, which amplifies use scope,
• Fundamental importance in future technologies – they are used in data components, electromotive mechanisms, medical equipment, and industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets and proposals for their use:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• They rust in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We suggest casing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex forms.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child health protection. Furthermore, small elements of these devices can be problematic in diagnostics medical after entering the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Breakaway strength of the magnet in ideal conditions – what it depends on?

Holding force of 112 kg is a result of laboratory testing performed under the following configuration:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• with a thickness of at least 10 mm
• characterized by lack of roughness
• without the slightest clearance between the magnet and steel
• under vertical force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

In practice, the actual holding force is determined by several key aspects, listed from most significant:

• Distance – the presence of foreign body (paint, tape, gap) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 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 maximum value.
• Steel thickness – too thin plate causes magnetic saturation, causing part of the power to be wasted into the air.
• Steel grade – ideal substrate is pure iron steel. Hardened steels may attract less.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Temperature influence – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity was measured with the use of a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.