MW 15x4 / N38 - cylindrical magnet

Pros and cons of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• Their magnetic field is maintained, and after approximately ten years it decreases only by ~1% (theoretically),
• Magnets effectively defend themselves against loss of magnetization caused by external fields,
• Thanks to the glossy finish, the plating of nickel, gold-plated, or silver-plated gives an modern appearance,
• Neodymium magnets achieve maximum magnetic induction on a small surface, which increases force concentration,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of custom creating and adapting to individual needs,
• Significant place in advanced technology sectors – they find application in computer drives, electric motors, diagnostic systems, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets lose 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
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Due to limitations in creating nuts and complicated forms in magnets, we recommend using casing - magnetic mechanism.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these products are able to be problematic in diagnostics medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what it depends on?

Magnet power was determined for optimal configuration, assuming:

• using a base made of low-carbon steel, serving as a circuit closing element
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by even structure
• with total lack of distance (no paint)
• during detachment in a direction perpendicular to the plane
• at temperature room level

Lifting capacity in practice – influencing factors

During everyday use, the actual lifting capacity is determined by a number of factors, listed from most significant:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is reached only during pulling at a 90° angle. The shear force of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Material type – ideal substrate is pure iron steel. Cast iron may generate lower lifting capacity.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was assessed by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the load capacity.