AM ucho [M8] - magnetic accessories

Advantages as well as disadvantages of neodymium magnets.

Apart from their consistent holding force, neodymium magnets have these key benefits:

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (in testing),
• Neodymium magnets prove to be highly resistant to demagnetization caused by external field sources,
• In other words, due to the smooth surface of nickel, the element becomes visually attractive,
• Neodymium magnets generate maximum magnetic induction on a contact point, which ensures high operational effectiveness,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of accurate shaping as well as optimizing to precise applications,
• Fundamental importance in electronics industry – they serve a role in computer drives, electric motors, medical equipment, and modern systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At very strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest casing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex shapes.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child health protection. It is also worth noting that tiny parts of these devices can disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what it depends on?

Breakaway force was defined for ideal contact conditions, including:

• using a base made of low-carbon steel, serving as a magnetic yoke
• with a cross-section no less than 10 mm
• with an ideally smooth touching surface
• under conditions of gap-free contact (metal-to-metal)
• for force applied at a right angle (in the magnet axis)
• at conditions approx. 20°C

Key elements affecting lifting force

Holding efficiency is influenced by working environment parameters, mainly (from priority):

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish 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 capacity drops significantly, often to levels of 20-30% of the nominal value.
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Metal type – different alloys reacts the same. Alloy additives worsen the interaction with the magnet.
• Surface quality – the more even the surface, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.