UMP 75x25 [M10x3] GW F200 PLATINIUM / N52 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after ten years, the decline in efficiency is only ~1% (based on calculations),
• They remain magnetized despite exposure to strong external fields,
• By applying a reflective layer of silver, the element gains a clean look,
• They have very high magnetic induction on the surface of the magnet,
• With the right combination of compounds, they reach significant thermal stability, enabling operation at or above 230°C (depending on the structure),
• With the option for customized forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Key role in advanced technical fields – they are utilized in HDDs, electric drives, diagnostic apparatus as well as high-tech tools,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, with minimal size,

Disadvantages of magnetic elements:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to physical collisions, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture and additionally strengthens its overall strength,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s profile). 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 protective material for outdoor use,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is not feasible,
• Potential hazard due to small fragments may arise, especially if swallowed, which is crucial in the family environments. Furthermore, minuscule fragments from these devices have the potential to interfere with diagnostics after being swallowed,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Maximum lifting capacity of the magnet – what contributes to it?

The given strength of the magnet represents the optimal strength, measured in the best circumstances, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with no separation
• with vertical force applied
• under standard ambient temperature

Lifting capacity in practice – influencing factors

Practical lifting force is determined by elements, by priority:

• Air gap between the magnet and the plate, as 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 a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.