UMS 20x8.6x4.5x7 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets.

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

• They do not lose magnetism, even during nearly ten years – the drop in strength is only ~1% (theoretically),
• Neodymium magnets prove to be highly resistant to magnetic field loss caused by magnetic disturbances,
• A magnet with a shiny gold surface has better aesthetics,
• The surface of neodymium magnets generates a unique magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of individual shaping and modifying to concrete requirements,
• Fundamental importance in modern industrial fields – they serve a role in mass storage devices, motor assemblies, medical equipment, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which enables their usage in small systems

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complex forms in magnets, we recommend using a housing - magnetic mechanism.
• Possible danger resulting from small fragments of magnets are risky, if swallowed, which becomes key in the context of child health protection. Additionally, small components of these products are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The load parameter shown represents the limit force, measured under optimal environment, meaning:

• using a plate made of low-carbon steel, functioning as a circuit closing element
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by smoothness
• with direct contact (no coatings)
• under axial force vector (90-degree angle)
• in stable room temperature

What influences lifting capacity in practice

Please note that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Clearance – the presence of any layer (paint, tape, air) interrupts the magnetic circuit, which reduces power rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits much less (typically approx. 20-30% of maximum force).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Rough surfaces weaken the grip.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet and the plate lowers the holding force.