MP 62x42x25 / N38 - ring magnet

Advantages and disadvantages of NdFeB magnets.

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

• Their power remains stable, and after approximately ten years it drops only by ~1% (theoretically),
• Neodymium magnets prove to be remarkably resistant to demagnetization caused by magnetic disturbances,
• Thanks to the shiny finish, the plating of Ni-Cu-Ni, gold, or silver-plated gives an modern appearance,
• Magnets have excellent magnetic induction on the outer side,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures approaching 230°C and above...
• Possibility of exact machining and adapting to atypical requirements,
• Wide application in innovative solutions – they are utilized in data components, electromotive mechanisms, precision medical tools, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which makes them useful in small systems

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding 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 those in rubber or plastics, which secure oxidation and corrosion.
• We suggest cover - magnetic mechanism, due to difficulties in creating threads inside the magnet and complicated shapes.
• Health risk to health – tiny shards of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, tiny parts of these products are able to disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Optimal lifting capacity of a neodymium magnet – what affects it?

Information about lifting capacity was defined for optimal configuration, including:

• using a base made of mild steel, serving as a circuit closing element
• with a cross-section of at least 10 mm
• characterized by even structure
• without the slightest insulating layer between the magnet and steel
• under axial force vector (90-degree angle)
• at standard ambient temperature

What influences lifting capacity in practice

In practice, the actual holding force depends on many variables, listed from most significant:

• Clearance – existence of foreign body (rust, dirt, air) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Metal type – different alloys reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface quality – the smoother and more polished the surface, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under perpendicular forces, whereas under shearing force the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet and the plate reduces the load capacity.