UMS 16x6.5x3.5x5 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They protect against demagnetization induced by surrounding electromagnetic environments very well,
• Thanks to the polished finish and gold coating, they have an aesthetic appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• With the right combination of magnetic alloys, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the form),
• With the option for customized forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving design adaptation,
• Significant impact in cutting-edge sectors – they are used in computer drives, electric motors, healthcare devices along with high-tech tools,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to mechanical hits, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture and additionally strengthens its overall strength,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on size). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• They rust in a humid environment, especially when used outside, we recommend using moisture-resistant magnets, such as those made of polymer,
• Limited ability to create internal holes in the magnet – the use of a magnetic holder is recommended,
• Possible threat from tiny pieces may arise, when consumed by mistake, which is significant in the family environments. Additionally, tiny components from these devices can disrupt scanning after being swallowed,
• Due to the price of neodymium, their cost is considerably higher,

Maximum holding power of the magnet – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, determined in ideal conditions, specifically:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• with vertical force applied
• under standard ambient temperature

Lifting capacity in real conditions – factors

Practical lifting force is determined by factors, by priority:

• Air gap between the magnet and the plate, since 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.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.