MW 8x1.5 / N38 - cylindrical magnet

Strengths and weaknesses of rare earth magnets.

Apart from their superior holding force, neodymium magnets have these key benefits:

• They do not lose power, even after nearly 10 years – the reduction in strength is only ~1% (theoretically),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• By using a shiny coating of nickel, the element presents an nice look,
• Magnetic induction on the working layer of the magnet remains very high,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling functioning at temperatures reaching 230°C and above...
• Possibility of accurate machining as well as modifying to atypical conditions,
• Fundamental importance in future technologies – they serve a role in data components, electric motors, diagnostic systems, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets and ways of using them

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We recommend casing - magnetic mount, due to difficulties in creating threads inside the magnet and complex forms.
• Health risk to health – tiny shards of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child safety. Additionally, small elements of these products can disrupt the diagnostic process medical when they are in the body.
• Due to complex production process, their price is higher than average,

Detachment force of the magnet in optimal conditions – what contributes to it?

The force parameter is a measurement result conducted under specific, ideal conditions:

• on a plate made of structural steel, optimally conducting the magnetic field
• whose thickness reaches at least 10 mm
• characterized by even structure
• under conditions of no distance (surface-to-surface)
• during pulling in a direction perpendicular to the mounting surface
• at ambient temperature room level

Determinants of practical lifting force of a magnet

Holding efficiency is influenced by specific conditions, including (from most important):

• Air gap (betwixt the magnet and the plate), because even a microscopic distance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Metal type – different alloys attracts identically. High carbon content weaken the attraction effect.
• Smoothness – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the holding force.