UMGGW 34x8 [M4] GW / N38 - magnetic holder rubber internal thread

Advantages and disadvantages of NdFeB magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• Their power is durable, and after around ten years it drops only by ~1% (theoretically),
• They feature excellent resistance to weakening of magnetic properties when exposed to opposing magnetic fields,
• By applying a lustrous layer of gold, the element acquires an proper look,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Possibility of custom machining as well as optimizing to precise applications,
• Significant place in advanced technology sectors – they are used in computer drives, electric motors, medical devices, and technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Drawbacks and weaknesses of neodymium magnets and proposals for their use:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. 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 those in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest a housing - magnetic mechanism, due to difficulties in producing threads inside the magnet and complicated shapes.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which becomes key in the context of child safety. Furthermore, small components of these devices can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

Holding force of 7.7 kg is a theoretical maximum value performed under the following configuration:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of gap-free contact (metal-to-metal)
• under perpendicular force vector (90-degree angle)
• at temperature room level

Practical aspects of lifting capacity – factors

Please note that the magnet holding will differ subject to the following factors, starting with the most relevant:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel type – mild steel attracts best. Higher carbon content reduce magnetic permeability and lifting capacity.
• Surface finish – full contact is obtained only on polished steel. Rough texture reduce the real contact area, reducing force.
• Temperature – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.