AM ucho [M8] - magnetic accessories

Pros and cons of rare earth magnets.

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

• They do not lose magnetism, even after approximately ten years – the decrease in strength is only ~1% (theoretically),
• They maintain their magnetic properties even under close interference source,
• The use of an refined layer of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnetic induction on the top side of the magnet turns out to be exceptional,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of accurate creating as well as modifying to specific needs,
• Fundamental importance in advanced technology sectors – they serve a role in magnetic memories, electromotive mechanisms, diagnostic systems, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which enables their usage in compact constructions

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited possibility of making nuts in the magnet and complex forms - recommended is cover - mounting mechanism.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small components of these products are able to be problematic in diagnostics medical after entering 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?

Magnet power is the result of a measurement for optimal configuration, assuming:

• using a sheet made of low-carbon steel, acting as a ideal flux conductor
• possessing a thickness of minimum 10 mm to avoid saturation
• with an ideally smooth contact surface
• under conditions of gap-free contact (metal-to-metal)
• during detachment in a direction vertical to the plane
• at conditions approx. 20°C

Key elements affecting lifting force

Bear in mind that the magnet holding may be lower depending on the following factors, starting with the most relevant:

• Distance (between the magnet and the metal), since even a microscopic clearance (e.g. 0.5 mm) results in a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Direction of force – highest force is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Alloy admixtures decrease magnetic properties and holding force.
• Surface structure – the smoother and more polished the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.