MPL 40x10x4x2[7/3.5] / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Besides their stability, neodymium magnets are valued for these benefits:

• They do not lose their magnetism, even after approximately ten years – the decrease of strength is only ~1% (theoretically),
• They protect against demagnetization induced by external electromagnetic environments effectively,
• The use of a mirror-like nickel surface provides a refined finish,
• They possess significant magnetic force measurable at the magnet’s surface,
• With the right combination of compounds, they reach increased thermal stability, enabling operation at or above 230°C (depending on the design),
• The ability for custom shaping and adjustment to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Key role in modern technologies – they are used in computer drives, rotating machines, healthcare devices and sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in compact constructions

Disadvantages of magnetic elements:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to physical collisions, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time reinforces its overall durability,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (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 moisture can corrode. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is not feasible,
• Possible threat linked to microscopic shards may arise, in case of ingestion, which is notable in the context of child safety. It should also be noted that miniature parts from these assemblies may interfere with diagnostics once in the system,
• Due to the price of neodymium, their cost is relatively high,

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

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

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• with vertical force applied
• at room temperature

Lifting capacity in real conditions – factors

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

• 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.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.