UMGGW 22x6 [M4] GW / N38 - magnetic holder rubber internal thread

Strengths as well as weaknesses of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• They maintain their magnetic properties even under external field action,
• By using a reflective coating of gold, the element gains an proper look,
• Magnetic induction on the top side of the magnet is impressive,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to freedom in forming and the capacity to modify to client solutions,
• Huge importance in future technologies – they serve a role in HDD drives, electric drive systems, medical devices, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• Neodymium magnets decrease their force 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
• They rust in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest a housing - magnetic mechanism, due to difficulties in realizing nuts inside the magnet and complex forms.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. It is also worth noting that tiny parts of these magnets can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The force parameter is a theoretical maximum value conducted under standard conditions:

• using a base made of mild steel, acting as a ideal flux conductor
• with a thickness minimum 10 mm
• with a surface cleaned and smooth
• without the slightest insulating layer between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at temperature room level

Magnet lifting force in use – key factors

In real-world applications, the real power is determined by several key aspects, presented from the most important:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Angle of force application – highest force is obtained only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick steel does not close the flux, causing part of the flux to be lost to the other side.
• Metal type – not every steel attracts identically. Alloy additives weaken the attraction effect.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling 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.