UMGW 20x15x7 [M4] GW / N38 - magnetic holder internal thread

Pros and cons of neodymium magnets.

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

• They retain full power for around 10 years – the drop is just ~1% (in theory),
• Neodymium magnets are extremely resistant to magnetic field loss caused by external magnetic fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Magnetic induction on the working layer of the magnet is exceptional,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to flexibility in shaping and the ability to modify to individual projects,
• Key role in high-tech industry – they serve a role in magnetic memories, electric motors, advanced medical instruments, also multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• At very strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their strength 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
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest cover - magnetic holder, due to difficulties in producing nuts inside the magnet and complex forms.
• Potential hazard to health – tiny shards of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. Additionally, small components of these magnets are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting capacity of the magnet – what affects it?

The load parameter shown concerns the limit force, recorded under ideal test conditions, specifically:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• with a thickness no less than 10 mm
• characterized by smoothness
• with zero gap (no coatings)
• under vertical force direction (90-degree angle)
• at room temperature

Determinants of practical lifting force of a magnet

Please note that the working load may be lower subject to the following factors, in order of importance:

• 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.
• Angle of force application – highest force is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Plate material – low-carbon steel attracts best. Higher carbon content decrease magnetic properties and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Thermal factor – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, however under shearing force the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate lowers the load capacity.