MP 20x8x5 / N38 - ring magnet

Pros as well as cons of NdFeB magnets.

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

• They do not lose magnetism, even during approximately ten years – the drop in lifting capacity is only ~1% (based on measurements),
• Neodymium magnets prove to be extremely resistant to magnetic field loss caused by external interference,
• The use of an aesthetic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the surface of the magnet remains maximum,
• Neodymium magnets are characterized by very 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...
• Thanks to the potential of accurate shaping and customization to unique projects, magnetic components can be modeled in a broad palette of shapes and sizes, which increases their versatility,
• Significant place in electronics industry – they are utilized in hard drives, drive modules, diagnostic systems, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which makes them useful in small systems

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a special holder, which not only secures them against impacts but also raises their 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 durability even at temperatures up to 230°C
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We recommend a housing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, tiny parts of these magnets can disrupt the diagnostic process medical when they are in the body.
• Due to expensive raw materials, their price is higher than average,

Maximum lifting capacity of the magnet – what affects it?

The specified lifting capacity concerns the maximum value, recorded under laboratory conditions, specifically:

• on a block made of structural steel, optimally conducting the magnetic field
• with a thickness minimum 10 mm
• with a plane cleaned and smooth
• under conditions of no distance (surface-to-surface)
• under perpendicular application of breakaway force (90-degree angle)
• in stable room temperature

Practical aspects of lifting capacity – factors

Real force is influenced by working environment parameters, such as (from most important):

• Gap between magnet and steel – every millimeter of separation (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits significantly lower power (typically approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of converting into lifting capacity.
• Plate material – mild steel gives the best results. Alloy admixtures reduce magnetic properties and holding force.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves field saturation. Rough surfaces reduce efficiency.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a minimal clearance {between} the magnet and the plate decreases the holding force.