UMH 42x9x46 [M6] / N38 - magnetic holder with hook

Strengths as well as weaknesses of rare earth magnets.

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

• They do not lose strength, even during nearly ten years – the drop in power is only ~1% (based on measurements),
• Neodymium magnets are characterized by extremely resistant to demagnetization caused by external magnetic fields,
• By using a lustrous coating of gold, the element acquires an elegant look,
• They are known for high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Thanks to freedom in shaping and the ability to modify to individual projects,
• Huge importance in electronics industry – they are commonly used in computer drives, brushless drives, precision medical tools, as well as technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a steel housing, which not only secures them against impacts but also increases 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 force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Due to limitations in realizing threads and complex forms in magnets, we propose using cover - magnetic mechanism.
• Potential hazard related to microscopic parts of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, tiny parts of these products can disrupt the diagnostic process medical in case of swallowing.
• With large orders the cost of neodymium magnets can be a barrier,

Highest magnetic holding force – what contributes to it?

Holding force of 66 kg is a result of laboratory testing performed under the following configuration:

• using a sheet made of mild steel, serving as a magnetic yoke
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a plane free of scratches
• with zero gap (without coatings)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Practical aspects of lifting capacity – factors

In real-world applications, the actual holding force is determined by many variables, listed from crucial:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – maximum parameter is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is usually several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Material composition – different alloys attracts identically. High carbon content worsen the attraction effect.
• Surface condition – ground elements guarantee perfect abutment, which increases force. Rough surfaces weaken the grip.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.