MW 5x15 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They have excellent resistance to magnetism drop when exposed to external magnetic sources,
• By applying a reflective coating of nickel, the element acquires an proper look,
• Magnets have exceptionally strong magnetic induction on the working surface,
• 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 the possibility of free shaping and customization to specialized needs, magnetic components can be manufactured in a wide range of geometric configurations, which expands the range of possible applications,
• Significant place in electronics industry – they are utilized in data components, brushless drives, medical devices, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Problematic aspects of neodymium magnets: application proposals

• At strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease 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
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in creating nuts and complicated shapes in magnets, we recommend using cover - magnetic mechanism.
• Possible danger related to microscopic parts of magnets are risky, if swallowed, which becomes key 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 in case of swallowing.
• With mass production the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what contributes to it?

Holding force of 4.15 kg is a measurement result conducted under standard conditions:

• on a base made of mild steel, effectively closing the magnetic field
• with a cross-section no less than 10 mm
• with an polished touching surface
• with zero gap (without paint)
• for force acting at a right angle (pull-off, not shear)
• at conditions approx. 20°C

Magnet lifting force in use – key factors

Holding efficiency impacted by specific conditions, including (from priority):

• Air gap (betwixt the magnet and the metal), since even a tiny clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Angle of force application – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly several times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin sheet does not close the flux, causing part of the power to be wasted into the air.
• Metal type – not every steel attracts identically. Alloy additives weaken the attraction effect.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was measured with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.