UMGZ 20x15x7 [M4] GZ / N38 - magnetic holder external thread

Strengths and weaknesses of NdFeB magnets.

Apart from their notable power, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Magnets effectively defend themselves against loss of magnetization caused by external fields,
• A magnet with a smooth nickel surface has better aesthetics,
• Magnets are distinguished by extremely high magnetic induction on the surface,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in shaping and the ability to adapt to complex applications,
• Versatile presence in electronics industry – they are used in hard drives, electric motors, medical devices, also industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We recommend a housing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complicated forms.
• Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small components of these magnets are able to be problematic in diagnostics medical after entering the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Optimal lifting capacity of a neodymium magnet – what it depends on?

Magnet power was defined for optimal configuration, taking into account:

• with the contact of a sheet made of low-carbon steel, ensuring full magnetic saturation
• whose thickness equals approx. 10 mm
• with an ideally smooth touching surface
• without the slightest air gap between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at room temperature

Practical aspects of lifting capacity – factors

In practice, the real power depends on many variables, listed from most significant:

• Distance – existence of any layer (rust, dirt, air) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Chemical composition of the base – mild steel gives the best results. Higher carbon content lower magnetic permeability and lifting capacity.
• Plate texture – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Operating temperature – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the holding force.