MW 8x1.5 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They retain attractive force for nearly 10 years – the drop is just ~1% (in theory),
• They have excellent resistance to weakening of magnetic properties due to opposing magnetic fields,
• A magnet with a shiny silver surface looks better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Thanks to freedom in forming and the ability to modify to complex applications,
• Fundamental importance in innovative solutions – they find application in mass storage devices, electric motors, diagnostic systems, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their power 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 when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complex shapes in magnets, we propose using cover - magnetic mount.
• Health risk related to microscopic parts of magnets are risky, if swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Magnetic strength at its maximum – what contributes to it?

Breakaway force was defined for optimal configuration, assuming:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• whose thickness reaches at least 10 mm
• with a surface free of scratches
• under conditions of no distance (metal-to-metal)
• during detachment in a direction perpendicular to the mounting surface
• at room temperature

Determinants of practical lifting force of a magnet

Holding efficiency is affected by working environment parameters, including (from priority):

• Gap between surfaces – every millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick sheet does not close the flux, causing part of the power to be escaped into the air.
• Metal type – different alloys attracts identically. Alloy additives worsen the attraction effect.
• Surface condition – ground elements ensure maximum contact, which improves field saturation. Rough surfaces weaken the grip.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the holding force.