UMH 20x7x35 [M4] / N38 - magnetic holder with hook

Advantages as well as disadvantages of rare earth magnets.

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

• They have unchanged lifting capacity, and over more than 10 years their performance decreases symbolically – ~1% (in testing),
• They are noted for resistance to demagnetization induced by external magnetic fields,
• In other words, due to the smooth layer of nickel, the element gains visual value,
• They are known for 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 form) even at a temperature of 230°C or more...
• Considering the ability of precise molding and customization to unique solutions, NdFeB magnets can be produced in a variety of forms and dimensions, which amplifies use scope,
• Significant place in future technologies – they find application in magnetic memories, brushless drives, precision medical tools, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in compact constructions

Cons of neodymium magnets: application proposals

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing nuts and complex forms in magnets, we propose using cover - magnetic holder.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical after entering the body.
• Due to expensive raw materials, their price is higher than average,

Magnetic strength at its maximum – what affects it?

Information about lifting capacity is the result of a measurement for the most favorable conditions, including:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• whose thickness equals approx. 10 mm
• with a plane cleaned and smooth
• without the slightest clearance between the magnet and steel
• during pulling in a direction vertical to the plane
• at ambient temperature room level

Practical lifting capacity: influencing factors

During everyday use, the real power results from several key aspects, listed from most significant:

• Space between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – maximum parameter is available only during perpendicular pulling. The shear force of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Material composition – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Temperature – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, however under shearing force the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.