HH 42x8.8 [M6] / N38 - through hole magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their immense strength, neodymium magnets offer the following advantages:

• Their strength remains stable, and after around 10 years, it drops only by ~1% (according to research),
• They protect against demagnetization induced by ambient electromagnetic environments remarkably well,
• The use of a decorative silver surface provides a refined finish,
• The outer field strength of the magnet shows remarkable magnetic properties,
• With the right combination of compounds, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the structure),
• The ability for custom shaping and adaptation to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Wide application in modern technologies – they are used in HDDs, electric drives, medical equipment as well as technologically developed systems,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of NdFeB magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to external force, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage while also strengthens its overall strength,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can degrade. Therefore, for outdoor applications, we suggest waterproof types made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing threads directly in the magnet,
• Safety concern related to magnet particles may arise, in case of ingestion, which is crucial in the family environments. Furthermore, miniature parts from these products can disrupt scanning when ingested,
• Due to a complex production process, their cost is relatively high,

Maximum lifting force for a neodymium magnet – what contributes to it?

The given strength of the magnet means the optimal strength, determined in ideal conditions, specifically:

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Determinants of lifting force in real conditions

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under parallel forces the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate reduces the holding force.