MW 5x30 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They have constant strength, and over around 10 years their performance decreases symbolically – ~1% (according to theory),
• Neodymium magnets are characterized by exceptionally resistant to loss of magnetic properties caused by external field sources,
• By applying a decorative coating of nickel, the element acquires an professional look,
• They show high magnetic induction at the operating surface, which increases their power,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures approaching 230°C and above...
• Thanks to the ability of free shaping and customization to custom requirements, NdFeB magnets can be manufactured in a variety of geometric configurations, which increases their versatility,
• Fundamental importance in modern industrial fields – they are commonly used in hard drives, drive modules, precision medical tools, as well as modern systems.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Drawbacks and weaknesses of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Limited ability of producing threads in the magnet and complicated shapes - recommended is cover - mounting mechanism.
• Health risk related to microscopic parts of magnets pose a threat, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these products can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Magnetic strength at its maximum – what affects it?

Breakaway force was defined for the most favorable conditions, taking into account:

• using a base made of mild steel, functioning as a magnetic yoke
• with a cross-section of at least 10 mm
• characterized by even structure
• without the slightest air gap between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• in neutral thermal conditions

Key elements affecting lifting force

Real force is affected by specific conditions, such as (from most important):

• Gap (betwixt the magnet and the metal), since even a tiny clearance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Steel type – mild steel gives the best results. Alloy steels lower magnetic permeability and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Thermal environment – heating the magnet results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate decreases the holding force.