UMP 50x20 [M8] GW / N38 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after 10 years, the performance loss is only ~1% (in laboratory conditions),
• They are extremely resistant to demagnetization caused by external magnetic sources,
• The use of a mirror-like nickel surface provides a smooth finish,
• The outer field strength of the magnet shows advanced magnetic properties,
• Thanks to their high temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• Thanks to the possibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in different geometries, which broadens their application range,
• Important function in new technology industries – they find application in computer drives, rotating machines, diagnostic apparatus or even other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which makes them useful in miniature devices

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to mechanical hits, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time enhances 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 form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a moist environment, especially when used outside, we recommend using encapsulated magnets, such as those made of polymer,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing complex structures directly in the magnet,
• Possible threat related to magnet particles may arise, especially if swallowed, which is significant in the context of child safety. Additionally, minuscule fragments from these devices can hinder health screening if inside the body,
• In cases of large-volume purchasing, neodymium magnet cost may not be economically viable,

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

The given lifting capacity of the magnet means the maximum lifting force, measured under optimal conditions, specifically:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• under perpendicular detachment force
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet is determined by in practice key elements, from primary to secondary:

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

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.