AM ucho [M12] - magnetic accessories

Strengths as well as weaknesses of rare earth magnets.

Apart from their notable power, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• Magnets perfectly defend themselves against loss of magnetization caused by external fields,
• By using a decorative coating of nickel, the element has an aesthetic look,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Thanks to modularity in designing and the capacity to modify to individual projects,
• Fundamental importance in innovative solutions – they serve a role in hard drives, brushless drives, medical equipment, also multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses 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 raises their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• We suggest casing - magnetic holder, due to difficulties in producing nuts inside the magnet and complex forms.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the context of child safety. Furthermore, tiny parts of these magnets are able to complicate diagnosis medical after entering the body.
• Due to neodymium price, their price is relatively high,

Maximum magnetic pulling force – what contributes to it?

Information about lifting capacity was determined for optimal configuration, assuming:

• on a block made of mild steel, perfectly concentrating the magnetic field
• possessing a thickness of min. 10 mm to ensure full flux closure
• with an ground touching surface
• without the slightest air gap between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at standard ambient temperature

Lifting capacity in practice – influencing factors

In real-world applications, the actual lifting capacity is determined by a number of factors, presented from most significant:

• Clearance – the presence of any layer (paint, dirt, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick sheet causes magnetic saturation, causing part of the flux to be escaped into the air.
• Material composition – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Unevenness acts like micro-gaps.
• Temperature influence – hot environment weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet and the plate decreases the holding force.