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

Advantages and disadvantages of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They maintain their magnetic properties even under strong external field,
• By covering with a shiny coating of nickel, the element has an professional look,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Thanks to freedom in forming and the capacity to modify to client solutions,
• Universal use in modern industrial fields – they find application in mass storage devices, electric drive systems, medical devices, also multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• 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 secures them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited possibility of creating nuts in the magnet and complicated shapes - preferred is cover - magnetic holder.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the context of child safety. Additionally, small elements of these devices are able to 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 can limit application in large quantities

Highest magnetic holding force – what affects it?

The lifting capacity listed is a result of laboratory testing conducted under standard conditions:

• on a plate made of structural steel, optimally conducting the magnetic flux
• with a thickness minimum 10 mm
• with an ideally smooth contact surface
• with total lack of distance (no impurities)
• under axial force direction (90-degree angle)
• at room temperature

Lifting capacity in practice – influencing factors

During everyday use, the real power is determined by many variables, listed from crucial:

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is reached only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• 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.
• Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Plate texture – ground elements guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Thermal environment – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet and the plate lowers the load capacity.