NCM 30x13.5x5 / N38 - channel magnetic holder

Advantages as well as disadvantages of rare earth magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They retain magnetic properties for nearly ten years – the drop is just ~1% (based on simulations),
• They possess excellent resistance to magnetic field loss when exposed to opposing magnetic fields,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Possibility of precise machining as well as modifying to complex conditions,
• Wide application in modern industrial fields – they are commonly used in mass storage devices, brushless drives, precision medical tools, and other advanced devices.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a special holder, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 extremely resistant to heat
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited ability of producing nuts in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small elements of these devices can disrupt the diagnostic process medical after entering the body.
• Due to neodymium price, their price is higher than average,

Magnetic strength at its maximum – what contributes to it?

The specified lifting capacity concerns the peak performance, obtained under ideal test conditions, specifically:

• with the use of a sheet made of special test steel, ensuring maximum field concentration
• possessing a thickness of minimum 10 mm to avoid saturation
• characterized by even structure
• with direct contact (no coatings)
• under perpendicular force direction (90-degree angle)
• in stable room temperature

Magnet lifting force in use – key factors

Holding efficiency impacted by specific conditions, mainly (from most important):

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of nominal force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel attracts identically. High carbon content weaken the attraction effect.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture reduce the real contact area, reducing force.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.