MW 18x1.5 / N38 - cylindrical magnet

Strengths and weaknesses of rare earth magnets.

Besides their remarkable strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• They maintain their magnetic properties even under external field action,
• By applying a smooth layer of gold, the element has an professional look,
• Magnetic induction on the working layer of the magnet remains strong,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures approaching 230°C and above...
• In view of the ability of precise forming and adaptation to individualized requirements, neodymium magnets can be produced in a wide range of shapes and sizes, which amplifies use scope,
• Significant place in modern technologies – they are utilized in hard drives, electromotive mechanisms, medical devices, also complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in miniature devices

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited ability of producing threads in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Health risk resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. Furthermore, tiny parts of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• Due to neodymium price, their price is higher than average,

Magnetic strength at its maximum – what contributes to it?

The declared magnet strength represents the maximum value, recorded under optimal environment, specifically:

• with the contact of a yoke made of special test steel, ensuring maximum field concentration
• with a cross-section minimum 10 mm
• with a surface cleaned and smooth
• under conditions of gap-free contact (metal-to-metal)
• under vertical force direction (90-degree angle)
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

Please note that the application force may be lower depending on elements below, in order of importance:

• Distance – the presence of foreign body (rust, tape, gap) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Steel thickness – too thin plate does not close the flux, causing part of the flux to be escaped into the air.
• Steel type – low-carbon steel gives the best results. Alloy admixtures decrease magnetic permeability and lifting capacity.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – high temperature reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity was assessed using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.