MP 20x8/4x5 / N38 - ring magnet

Pros and cons of neodymium magnets.

Besides their tremendous field intensity, neodymium magnets offer the following advantages:

• Their power is durable, and after around ten years it drops only by ~1% (according to research),
• They maintain their magnetic properties even under strong external field,
• Thanks to the glossy finish, the coating of Ni-Cu-Ni, gold-plated, or silver-plated gives an modern appearance,
• The surface of neodymium magnets generates a strong magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of individual modeling as well as adjusting to individual applications,
• Universal use in high-tech industry – they find application in computer drives, motor assemblies, advanced medical instruments, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which makes them useful in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• We suggest casing - magnetic mount, due to difficulties in creating threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices are able to be problematic in diagnostics medical after entering the body.
• Due to complex production process, their price is higher than average,

Detachment force of the magnet in optimal conditions – what affects it?

The load parameter shown refers to the limit force, recorded under ideal test conditions, specifically:

• on a plate made of structural steel, optimally conducting the magnetic flux
• with a cross-section minimum 10 mm
• with an ideally smooth contact surface
• without the slightest air gap between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at temperature room level

Practical aspects of lifting capacity – factors

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

• Clearance – the presence of foreign body (paint, tape, air) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin sheet causes magnetic saturation, causing part of the power to be wasted into the air.
• Chemical composition of the base – mild steel gives the best results. Alloy steels decrease magnetic properties and lifting capacity.
• Plate texture – smooth surfaces guarantee perfect abutment, which improves field saturation. Uneven metal reduce efficiency.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was assessed using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.