MPL 30x15x10 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their exceptional strength, neodymium magnets offer the following advantages:

• They do not lose their even over around ten years – the loss of strength is only ~1% (according to tests),
• Their ability to resist magnetic interference from external fields is impressive,
• By applying a bright layer of silver, the element gains a sleek look,
• They have extremely strong magnetic induction on the surface of the magnet,
• Thanks to their exceptional temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• The ability for accurate shaping or adaptation to custom needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Important function in new technology industries – they are used in computer drives, electric drives, diagnostic apparatus and technologically developed systems,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, in miniature format,

Disadvantages of neodymium magnets:

• They can break 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 damage and additionally reinforces its overall robustness,
• 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 structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we recommend waterproof types made of rubber,
• Limited ability to create precision features in the magnet – the use of a housing is recommended,
• Possible threat linked to microscopic shards may arise, when consumed by mistake, which is crucial in the health of young users. It should also be noted that small elements from these magnets can complicate medical imaging once in the system,
• Due to the price of neodymium, their cost is considerably higher,

Maximum lifting force for a neodymium magnet – what contributes to it?

The given holding capacity of the magnet represents the highest holding force, calculated in the best circumstances, specifically:

• 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 polished side
• with zero air gap
• with vertical force applied
• at room temperature

Key elements affecting lifting force

Practical lifting force is dependent on factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because 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 was determined with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.