MW 6x2 / N38 - cylindrical magnet

Pros and cons of neodymium magnets.

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

• They do not lose power, even after approximately 10 years – the reduction in power is only ~1% (based on measurements),
• They do not lose their magnetic properties even under external field action,
• A magnet with a metallic nickel surface has better aesthetics,
• Magnets have maximum magnetic induction on the working surface,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• In view of the potential of accurate shaping and adaptation to individualized requirements, magnetic components can be created in a broad palette of geometric configurations, which makes them more universal,
• Versatile presence in high-tech industry – they find application in hard drives, electric drive systems, precision medical tools, also complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of creating threads in the magnet and complex shapes - preferred is a housing - magnet mounting.
• Potential hazard to health – tiny shards of magnets are risky, when accidentally swallowed, which gains importance in the context of child safety. Furthermore, small elements of these devices can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

Holding force of 0.66 kg is a result of laboratory testing performed under the following configuration:

• on a base made of mild steel, optimally conducting the magnetic flux
• possessing a thickness of min. 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature room level

Magnet lifting force in use – key factors

Effective lifting capacity is affected by working environment parameters, mainly (from most important):

• Space between magnet and steel – every millimeter of distance (caused e.g. by veneer or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Angle of force application – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin steel does not close the flux, causing part of the power to be lost to the other side.
• Plate material – low-carbon steel attracts best. Alloy admixtures lower magnetic properties and lifting capacity.
• Base smoothness – the more even the surface, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet and the plate decreases the holding force.