MW 9x3 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (according to literature),
• They possess excellent resistance to weakening of magnetic properties as a result of opposing magnetic fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to look better,
• Magnets have very high magnetic induction on the outer side,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Thanks to modularity in constructing and the capacity to modify to individual projects,
• Universal use in high-tech industry – they are commonly used in computer drives, brushless drives, advanced medical instruments, and industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets lose their force 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
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing nuts and complicated forms in magnets, we recommend using casing - magnetic holder.
• Health risk resulting from small fragments of magnets pose a threat, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these devices can be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is economically unviable,

Detachment force of the magnet in optimal conditions – what it depends on?

Holding force of 1.49 kg is a measurement result conducted under the following configuration:

• on a block made of structural steel, perfectly concentrating the magnetic flux
• possessing a thickness of minimum 10 mm to ensure full flux closure
• with an ideally smooth contact surface
• with total lack of distance (no impurities)
• for force applied at a right angle (pull-off, not shear)
• at standard ambient temperature

What influences lifting capacity in practice

It is worth knowing that the application force may be lower subject to elements below, in order of importance:

• Clearance – existence of any layer (paint, tape, gap) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of generating force.
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures lower magnetic properties and lifting capacity.
• Surface structure – the more even the plate, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet and the plate reduces the holding force.