MP 12x8/4x3 / N38 - ring magnet

Advantages as well as disadvantages of rare earth magnets.

Besides their immense magnetic power, neodymium magnets offer the following advantages:

• They do not lose strength, even during approximately ten years – the reduction in lifting capacity is only ~1% (theoretically),
• Neodymium magnets remain highly resistant to loss of magnetic properties caused by external interference,
• By applying a decorative coating of nickel, the element presents an nice look,
• Magnetic induction on the surface of the magnet remains very high,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of accurate machining as well as optimizing to specific requirements,
• Significant place in modern industrial fields – they are used in data components, electromotive mechanisms, advanced medical instruments, and other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Problematic aspects of neodymium magnets: tips and applications.

• At very strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• 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 forms - recommended is casing - magnet mounting.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. It is also worth noting that tiny parts of these devices are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what contributes to it?

Information about lifting capacity was determined for ideal contact conditions, assuming:

• on a base made of mild steel, optimally conducting the magnetic flux
• possessing a thickness of min. 10 mm to avoid saturation
• with an ground touching surface
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the plane
• at ambient temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

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

• Gap (betwixt the magnet and the plate), since even a very small distance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Load vector – maximum parameter is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is pure iron steel. Cast iron may attract less.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.