UMGGW 29x8 [M4] GW / N38 - magnetic holder rubber internal thread

Strengths and weaknesses of neodymium magnets.

Besides their immense strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• Neodymium magnets remain extremely resistant to magnetic field loss caused by external magnetic fields,
• The use of an metallic coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• Neodymium magnets create maximum magnetic induction on a small area, which increases force concentration,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures reaching 230°C and above...
• Considering the ability of free forming and customization to specialized needs, NdFeB magnets can be created in a wide range of forms and dimensions, which makes them more universal,
• Significant place in modern industrial fields – they are used in HDD drives, motor assemblies, diagnostic systems, and modern systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets decrease their strength 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 magnets in rubber or plastics, which secure oxidation as well as corrosion.
• We suggest a housing - magnetic mechanism, due to difficulties in realizing nuts inside the magnet and complicated shapes.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small components of these products can be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting capacity of the magnet – what contributes to it?

The load parameter shown concerns the limit force, obtained under laboratory conditions, specifically:

• on a base made of structural steel, optimally conducting the magnetic field
• whose transverse dimension is min. 10 mm
• with a plane cleaned and smooth
• without the slightest clearance between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Lifting capacity in real conditions – factors

It is worth knowing that the working load may be lower depending on the following factors, starting with the most relevant:

• Gap (betwixt the magnet and the metal), because even a microscopic distance (e.g. 0.5 mm) can cause a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Force direction – 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.
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel type – mild steel gives the best results. Higher carbon content decrease magnetic properties and holding force.
• Surface finish – ideal contact is obtained only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined by applying a steel plate with a smooth surface of optimal 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 reduces the holding force.