MW 10x30 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
• They show high resistance to demagnetization induced by external field influence,
• By covering with a reflective layer of gold, the element presents an professional look,
• Neodymium magnets ensure maximum magnetic induction on a their surface, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures approaching 230°C and above...
• Thanks to the possibility of precise molding and adaptation to unique solutions, magnetic components can be produced in a wide range of shapes and sizes, which amplifies use scope,
• Versatile presence in modern industrial fields – they are utilized in hard drives, brushless drives, medical devices, and modern systems.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They rust in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complicated shapes in magnets, we propose using cover - magnetic holder.
• Possible danger related to microscopic parts of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these products can complicate diagnosis medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what contributes to it?

Breakaway force was determined for ideal contact conditions, assuming:

• on a base made of structural steel, perfectly concentrating the magnetic flux
• with a thickness no less than 10 mm
• with an polished contact surface
• without the slightest clearance between the magnet and steel
• under axial force direction (90-degree angle)
• at temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

Effective lifting capacity impacted by working environment parameters, mainly (from priority):

• Air gap (betwixt the magnet and the metal), because even a very small clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped into the air.
• Plate material – low-carbon steel attracts best. Alloy admixtures lower magnetic permeability and lifting capacity.
• Smoothness – ideal contact is obtained only on smooth steel. Rough texture create air cushions, reducing force.
• Temperature – temperature increase causes a temporary drop of force. Check the thermal limit for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet and the plate lowers the holding force.