MPL 10x4x1.5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their notable magnetic energy, neodymium magnets have these key benefits:

• Their strength is durable, and after around 10 years, it drops only by ~1% (according to research),
• Their ability to resist magnetic interference from external fields is among the best,
• The use of a decorative gold surface provides a refined finish,
• Magnetic induction on the surface of these magnets is impressively powerful,
• Thanks to their enhanced temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in various configurations, which increases their application range,
• Important function in advanced technical fields – they find application in data storage devices, electric drives, medical equipment and high-tech tools,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a strong 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 breakage , and at the same time enhances its overall strength,
• Magnets lose pulling force 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 moisture can corrode. Therefore, for outdoor applications, we recommend waterproof types made of non-metallic composites,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is difficult,
• Possible threat related to magnet particles may arise, if ingested accidentally, which is important in the health of young users. Furthermore, miniature parts from these magnets may complicate medical imaging once in the system,
• Due to the price of neodymium, their cost is relatively high,

Maximum holding power of the magnet – what affects it?

The given strength of the magnet represents the optimal strength, calculated under optimal conditions, that is:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• 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.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, however under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate decreases the load capacity.