MW 8x15 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

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

• They retain attractive force for almost ten years – the drop is just ~1% (according to analyses),
• Magnets very well protect themselves against demagnetization caused by external fields,
• Thanks to the metallic finish, the coating of Ni-Cu-Ni, gold-plated, or silver-plated gives an elegant appearance,
• Neodymium magnets achieve maximum magnetic induction on a contact point, which ensures high operational effectiveness,
• 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...
• In view of the ability of flexible forming and adaptation to individualized requirements, magnetic components can be modeled in a wide range of geometric configurations, which expands the range of possible applications,
• Versatile presence in electronics industry – they are commonly used in mass storage devices, electromotive mechanisms, medical equipment, also multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose their power 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• We recommend a housing - magnetic mount, due to difficulties in realizing threads inside the magnet and complex forms.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these products can complicate diagnosis medical after entering the body.
• With mass production the cost of neodymium magnets is economically unviable,

Highest magnetic holding force – what contributes to it?

Magnet power was determined for ideal contact conditions, assuming:

• on a base made of mild steel, perfectly concentrating the magnetic flux
• whose transverse dimension equals approx. 10 mm
• with a plane free of scratches
• under conditions of gap-free contact (metal-to-metal)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

In real-world applications, the actual holding force depends on many variables, ranked from the most important:

• Distance (between the magnet and the plate), because even a microscopic clearance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Plate material – mild steel gives the best results. Alloy steels lower magnetic permeability and lifting capacity.
• Surface finish – full contact is obtained only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Thermal factor – high temperature reduces pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.