MW 29x10 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain attractive force for almost ten years – the drop is just ~1% (in theory),
• Magnets very well resist against loss of magnetization caused by foreign field sources,
• A magnet with a shiny gold surface has better aesthetics,
• Neodymium magnets achieve maximum magnetic induction on a their surface, which ensures high operational effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Considering the option of free shaping and adaptation to custom projects, NdFeB magnets can be manufactured in a wide range of geometric configurations, which expands the range of possible applications,
• Key role in advanced technology sectors – they find application in magnetic memories, brushless drives, diagnostic systems, as well as modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power 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
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of making threads in the magnet and complicated forms - recommended is a housing - mounting mechanism.
• Possible danger related to microscopic parts of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Furthermore, tiny parts of these magnets are able to complicate diagnosis medical in case of swallowing.
• Due to complex production process, their price is higher than average,

Maximum lifting force for a neodymium magnet – what affects it?

Holding force of 16.04 kg is a result of laboratory testing conducted under specific, ideal conditions:

• with the use of a sheet made of special test steel, ensuring full magnetic saturation
• whose transverse dimension reaches at least 10 mm
• with a plane perfectly flat
• without any insulating layer between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at ambient temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

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

• Distance – existence of foreign body (rust, dirt, gap) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of maximum force).
• Base massiveness – insufficiently thick steel does not accept the full field, causing part of the flux to be lost to the other side.
• Material type – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Surface finish – ideal contact is possible only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage 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 load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet and the plate reduces the holding force.