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

Pros as well as cons of rare earth magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They retain full power for around ten years – the loss is just ~1% (based on simulations),
• They possess excellent resistance to magnetic field loss when exposed to external fields,
• Thanks to the shiny finish, the plating of nickel, gold-plated, or silver-plated gives an visually attractive appearance,
• The surface of neodymium magnets generates a intense magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to versatility in constructing and the capacity to adapt to client solutions,
• Huge importance in innovative solutions – they are commonly used in computer drives, drive modules, advanced medical instruments, and technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in compact constructions

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of making threads in the magnet and complex forms - recommended is cover - mounting mechanism.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, small elements of these magnets are able to complicate diagnosis medical when they are in the body.
• With large orders the cost of neodymium magnets is a challenge,

Maximum lifting capacity of the magnet – what affects it?

Information about lifting capacity was defined for optimal configuration, assuming:

• with the application of a sheet made of low-carbon steel, ensuring maximum field concentration
• with a cross-section no less than 10 mm
• with a plane cleaned and smooth
• with zero gap (without paint)
• for force applied at a right angle (pull-off, not shear)
• in stable room temperature

Determinants of practical lifting force of a magnet

In practice, the real power is determined by a number of factors, ranked from most significant:

• Clearance – existence of foreign body (rust, tape, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick steel does not accept the full field, causing part of the power to be lost to the other side.
• Plate material – mild steel gives the best results. Higher carbon content lower magnetic properties and lifting capacity.
• Surface quality – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.