MW 9x3 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They retain full power for almost 10 years – the loss is just ~1% (in theory),
• Magnets perfectly protect themselves against loss of magnetization caused by ambient magnetic noise,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They show high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Considering the ability of free forming and customization to unique needs, NdFeB magnets can be produced in a broad palette of forms and dimensions, which expands the range of possible applications,
• Fundamental importance in modern industrial fields – they serve a role in computer drives, motor assemblies, medical equipment, also multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated shapes.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Highest magnetic holding force – what contributes to it?

Information about lifting capacity is the result of a measurement for the most favorable conditions, taking into account:

• using a base made of high-permeability steel, acting as a circuit closing element
• with a thickness of at least 10 mm
• with a plane free of scratches
• with zero gap (without paint)
• for force applied at a right angle (in the magnet axis)
• at ambient temperature room level

Magnet lifting force in use – key factors

In practice, the real power results from several key aspects, listed from crucial:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Metal type – not every steel reacts the same. High carbon content worsen the interaction with the magnet.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – heating the magnet causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.