MW 8x20 / N38 - cylindrical magnet

Pros as well as cons of neodymium magnets.

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

• They do not lose strength, even during around 10 years – the decrease in lifting capacity is only ~1% (according to tests),
• Neodymium magnets are distinguished by remarkably resistant to loss of magnetic properties caused by external field sources,
• A magnet with a smooth gold surface is more attractive,
• Magnetic induction on the working layer of the magnet is very high,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of precise modeling and adapting to individual needs,
• Wide application in advanced technology sectors – they serve a role in mass storage devices, drive modules, precision medical tools, also technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Cons of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a special holder, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose their strength 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 durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of making nuts in the magnet and complicated shapes - recommended is cover - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that tiny parts of these products are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what affects it?

Magnet power was defined for the most favorable conditions, assuming:

• on a plate made of mild steel, perfectly concentrating the magnetic flux
• possessing a thickness of at least 10 mm to avoid saturation
• with a plane free of scratches
• without the slightest air gap between the magnet and steel
• during pulling in a direction vertical to the plane
• at ambient temperature room level

Magnet lifting force in use – key factors

It is worth knowing that the working load will differ depending on elements below, in order of importance:

• Gap between surfaces – every millimeter of distance (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during pulling at a 90° angle. The shear force of the magnet along the surface is usually several times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Temperature – heating the magnet results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.