UMP 107x40 [M8+M10] GW F 400 kg / N38 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their remarkable field intensity, neodymium magnets offer the following advantages:

• Their strength is durable, and after around ten years, it drops only by ~1% (according to research),
• They protect against demagnetization induced by surrounding magnetic fields very well,
• In other words, due to the shiny nickel coating, the magnet obtains an aesthetic appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which expands their usage potential,
• Wide application in modern technologies – they are used in data storage devices, rotating machines, clinical machines or even technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which makes them ideal in small systems

Disadvantages of rare earth magnets:

• They may fracture when subjected to a sudden impact. If the magnets are exposed to physical collisions, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time strengthens its overall strength,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of synthetic coating for outdoor use,
• Limited ability to create precision features in the magnet – the use of a external casing is recommended,
• Safety concern linked to microscopic shards may arise, especially if swallowed, which is crucial in the health of young users. It should also be noted that small elements from these magnets may disrupt scanning if inside the body,
• Due to expensive raw materials, their cost is relatively high,

Detachment force of the magnet in optimal conditions – what contributes to it?

The given strength of the magnet corresponds to the optimal strength, calculated under optimal conditions, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Determinants of lifting force in real conditions

Practical lifting force is dependent on factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.