UMS 20x8.6x4.5x7 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years, the decline in efficiency is only ~1% (based on calculations),
• They are highly resistant to demagnetization caused by external magnetic sources,
• The use of a decorative gold surface provides a smooth finish,
• The outer field strength of the magnet shows advanced magnetic properties,
• Thanks to their exceptional temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• The ability for precise shaping or customization to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
• Important function in new technology industries – they serve a purpose in computer drives, electric drives, healthcare devices along with high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which makes them useful in miniature devices

Disadvantages of rare earth magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall durability,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss 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,
• Magnets exposed to moisture can rust. Therefore, for outdoor applications, it's best to use waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Potential hazard due to small fragments may arise, in case of ingestion, which is important in the protection of children. Additionally, small elements from these magnets can complicate medical imaging if inside the body,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Breakaway strength of the magnet in ideal conditions – what it depends on?

The given pulling force of the magnet corresponds to the maximum force, determined in a perfect environment, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• with vertical force applied
• at room temperature

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is affected by these factors, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes 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 performed on plates with a smooth surface of suitable thickness, under perpendicular forces, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.