HH 16x5.3 [M3] / N38 - through hole magnetic holder

Advantages and disadvantages of neodymium magnets.

Besides their exceptional magnetic power, neodymium magnets offer the following advantages:

• They have stable power, and over more than ten years their performance decreases symbolically – ~1% (in testing),
• They show high resistance to demagnetization induced by external disturbances,
• Thanks to the smooth finish, the coating of Ni-Cu-Ni, gold-plated, or silver-plated gives an professional appearance,
• Magnets have excellent magnetic induction on the working surface,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to versatility in designing and the ability to modify to complex applications,
• Universal use in modern technologies – they are commonly used in mass storage devices, motor assemblies, diagnostic systems, and technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which allows their use in compact constructions

Drawbacks and weaknesses of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and 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
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited possibility of creating threads in the magnet and complicated shapes - recommended is cover - mounting mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Furthermore, tiny parts of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what affects it?

The declared magnet strength represents the limit force, recorded under ideal test conditions, meaning:

• on a block made of mild steel, effectively closing the magnetic flux
• whose thickness reaches at least 10 mm
• characterized by even structure
• without any air gap between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Key elements affecting lifting force

In practice, the actual lifting capacity is determined by several key aspects, ranked from the most important:

• Gap (between the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to paint, corrosion or debris).
• Angle of force application – highest force is obtained only during pulling at a 90° angle. The shear force of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
• Metal type – different alloys attracts identically. High carbon content weaken the attraction effect.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases field saturation. Uneven metal reduce efficiency.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet and the plate lowers the lifting capacity.