UMP 29x10 [M5] GW - search holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for nearly ten years – the loss is just ~1% (according to analyses),
• Their ability to resist magnetic interference from external fields is notable,
• Because of the reflective layer of gold, the component looks aesthetically refined,
• The outer field strength of the magnet shows remarkable magnetic properties,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• The ability for custom shaping or adjustment to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Wide application in cutting-edge sectors – they serve a purpose in HDDs, rotating machines, medical equipment and high-tech tools,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to mechanical hits, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage and additionally reinforces its overall resistance,
• They lose field intensity at increased temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of protective material for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing fine shapes directly in the magnet,
• Health risk linked to microscopic shards may arise, if ingested accidentally, which is significant in the protection of children. Additionally, small elements from these devices may hinder health screening if inside the body,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

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

The given strength of the magnet represents the optimal strength, determined in the best circumstances, that is:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• under standard ambient temperature

Practical lifting capacity: influencing factors

The lifting capacity of a magnet depends on in practice the following factors, according to their importance:

• 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 checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, 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’s surface and the plate reduces the load capacity.