MW 8x1.5 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (according to literature),
• Magnets effectively defend themselves against demagnetization caused by external fields,
• Thanks to the shimmering finish, the plating of Ni-Cu-Ni, gold-plated, or silver gives an elegant appearance,
• The surface of neodymium magnets generates a strong magnetic field – this is a distinguishing feature,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Considering the option of free molding and customization to individualized solutions, neodymium magnets can be modeled in a variety of shapes and sizes, which makes them more universal,
• Wide application in high-tech industry – they are used in HDD drives, electromotive mechanisms, precision medical tools, and technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of making nuts in the magnet and complicated shapes - recommended is cover - magnetic holder.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Additionally, small components of these products are able to disrupt the diagnostic process medical when they are in 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 contributes to it?

The specified lifting capacity concerns the peak performance, recorded under optimal environment, namely:

• using a plate made of low-carbon steel, acting as a magnetic yoke
• possessing a thickness of at least 10 mm to ensure full flux closure
• with an ground contact surface
• with total lack of distance (no coatings)
• under axial application of breakaway force (90-degree angle)
• at room temperature

Lifting capacity in practice – influencing factors

Please note that the application force may be lower subject to the following factors, in order of importance:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is obtained 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. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material type – the best choice is pure iron steel. Stainless steels may attract less.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.