UMT 12x20 green / N38 - board holder

Strengths as well as weaknesses of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• They are resistant to demagnetization induced by presence of other magnetic fields,
• The use of an refined coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnetic induction on the working part of the magnet turns out to be impressive,
• Neodymium magnets are characterized by extremely 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 versatility in designing and the ability to modify to specific needs,
• Fundamental importance in high-tech industry – they are utilized in computer drives, electric drive systems, precision medical tools, also multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Problematic aspects of neodymium magnets: application proposals

• At 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.
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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 extremely resistant to heat
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small elements of these magnets can disrupt the diagnostic process medical when they are in the body.
• Due to complex production process, their price exceeds standard values,

Maximum magnetic pulling force – what contributes to it?

Magnet power was determined for ideal contact conditions, including:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• possessing a thickness of at least 10 mm to avoid saturation
• characterized by lack of roughness
• under conditions of gap-free contact (surface-to-surface)
• for force applied at a right angle (in the magnet axis)
• at room temperature

Determinants of practical lifting force of a magnet

Bear in mind that the application force may be lower influenced by elements below, in order of importance:

• Air gap (between the magnet and the plate), as even a very small distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material type – ideal substrate is pure iron steel. Hardened steels may attract less.
• Smoothness – ideal contact is obtained only on smooth steel. Rough texture create air cushions, reducing force.
• Thermal environment – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.