MW 8x1.5 / N38 - cylindrical magnet

Strengths and weaknesses of rare earth magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (according to theory),
• Neodymium magnets prove to be remarkably resistant to magnetic field loss caused by magnetic disturbances,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the top side of the magnet remains strong,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to flexibility in designing and the capacity to customize to individual projects,
• Versatile presence in future technologies – they are used in mass storage devices, electric motors, advanced medical instruments, also modern systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Cons of neodymium magnets: weaknesses and usage proposals

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Limited possibility of making threads in the magnet and complicated shapes - recommended is a housing - mounting mechanism.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Additionally, tiny parts of these products can complicate diagnosis medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Maximum magnetic pulling force – what contributes to it?

Breakaway force was determined for optimal configuration, taking into account:

• using a base made of high-permeability steel, acting as a circuit closing element
• with a thickness of at least 10 mm
• with a plane perfectly flat
• under conditions of no distance (metal-to-metal)
• for force applied at a right angle (in the magnet axis)
• at ambient temperature room level

Magnet lifting force in use – key factors

It is worth knowing that the working load may be lower influenced by elements below, in order of importance:

• Distance – the presence of foreign body (paint, tape, air) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin plate causes magnetic saturation, causing part of the flux to be lost to the other side.
• Material composition – different alloys reacts the same. Alloy additives worsen the attraction effect.
• Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces reduce efficiency.
• Thermal environment – temperature increase causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* 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 holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.