AM ucho [M12] - magnetic accessories

Pros and cons of NdFeB magnets.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They do not lose power, even during around ten years – the reduction in lifting capacity is only ~1% (theoretically),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• In other words, due to the shiny layer of gold, the element looks attractive,
• Magnetic induction on the working part of the magnet is very high,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to the option of free molding and customization to unique projects, magnetic components can be produced in a wide range of shapes and sizes, which increases their versatility,
• Universal use in modern industrial fields – they find application in data components, electromotive mechanisms, precision medical tools, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Drawbacks and weaknesses of neodymium magnets and proposals for their use:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their 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 stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited possibility of making nuts in the magnet and complicated shapes - preferred is a housing - magnet mounting.
• Potential hazard related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Additionally, small components of these magnets can disrupt the diagnostic process medical in case of swallowing.
• Due to expensive raw materials, their price exceeds standard values,

Maximum magnetic pulling force – what affects it?

Holding force of 480 kg is a theoretical maximum value conducted under specific, ideal conditions:

• on a plate made of structural steel, optimally conducting the magnetic flux
• whose transverse dimension is min. 10 mm
• characterized by lack of roughness
• under conditions of ideal adhesion (metal-to-metal)
• under perpendicular force direction (90-degree angle)
• at standard ambient temperature

Lifting capacity in practice – influencing factors

In real-world applications, the real power depends on a number of factors, ranked from crucial:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – highest force is available only during perpendicular pulling. The force required to slide of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin plate does not accept the full field, causing part of the power to be wasted to the other side.
• Steel type – low-carbon steel gives the best results. Alloy steels lower magnetic properties and lifting capacity.
• Surface quality – the more even the plate, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Temperature – temperature increase results in weakening of induction. Check the thermal limit for a given model.

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.