MW 20x18 / N38 - cylindrical magnet

Pros as well as cons of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain full power for around 10 years – the drop is just ~1% (according to analyses),
• They do not lose their magnetic properties even under close interference source,
• A magnet with a smooth gold surface is more attractive,
• Neodymium magnets generate maximum magnetic induction on a their surface, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to the possibility of precise molding and adaptation to individualized needs, NdFeB magnets can be modeled in a wide range of shapes and sizes, which increases their versatility,
• Huge importance in electronics industry – they serve a role in magnetic memories, electric drive systems, medical devices, as well as modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously improves 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 power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complicated shapes in magnets, we recommend using a housing - magnetic mechanism.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, small components of these devices are able to be problematic in diagnostics medical after entering the body.
• Due to neodymium price, their price is higher than average,

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The force parameter is a theoretical maximum value executed under standard conditions:

• with the contact of a sheet made of special test steel, ensuring full magnetic saturation
• whose thickness reaches at least 10 mm
• with a surface perfectly flat
• without the slightest clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Practical lifting capacity: influencing factors

Real force is influenced by specific conditions, including (from priority):

• Clearance – existence of any layer (rust, tape, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (often 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.
• Metal type – different alloys attracts identically. High carbon content worsen the attraction effect.
• Base smoothness – the more even the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – temperature increase results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the holding force.