MW 33x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of NdFeB magnets.

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

• They have stable power, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• Magnets effectively resist against loss of magnetization caused by ambient magnetic noise,
• Thanks to the smooth finish, the surface of nickel, gold, or silver gives an professional appearance,
• They show high magnetic induction at the operating surface, making them more effective,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to modularity in shaping and the ability to adapt to specific needs,
• Wide application in innovative solutions – they are utilized in mass storage devices, brushless drives, precision medical tools, also multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and ways of using them

• At strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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 suggest using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing threads and complex shapes in magnets, we recommend using cover - magnetic mount.
• Possible danger related to microscopic parts of magnets are risky, if swallowed, which gains importance in the context of child health protection. Additionally, small elements of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what it depends on?

The specified lifting capacity concerns the peak performance, obtained under optimal environment, meaning:

• using a base made of low-carbon steel, serving as a circuit closing element
• with a cross-section no less than 10 mm
• characterized by smoothness
• with total lack of distance (no impurities)
• under vertical force vector (90-degree angle)
• at conditions approx. 20°C

Impact of factors on magnetic holding capacity in practice

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

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Material composition – different alloys attracts identically. Alloy additives weaken the interaction with the magnet.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was determined using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, however under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.