MPL 30x15x2 / N38 - lamellar magnet

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 10 years – the drop is just ~1% (based on simulations),
• They protect against demagnetization induced by ambient magnetic influence very well,
• In other words, due to the shiny nickel coating, the magnet obtains an stylish appearance,
• The outer field strength of the magnet shows advanced magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Thanks to the freedom in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in different geometries, which expands their usage potential,
• Significant impact in new technology industries – they are used in hard drives, rotating machines, medical equipment or even sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in compact dimensions, which makes them ideal in miniature devices

Disadvantages of magnetic elements:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to shocks, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage and additionally reinforces its overall strength,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (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,
• Magnets exposed to damp air can rust. Therefore, for outdoor applications, we recommend waterproof types made of non-metallic composites,
• Limited ability to create complex details in the magnet – the use of a mechanical support is recommended,
• Potential hazard related to magnet particles may arise, if ingested accidentally, which is important in the protection of children. Additionally, small elements from these products may hinder health screening once in the system,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Maximum holding power of the magnet – what it depends on?

The given strength of the magnet represents the optimal strength, calculated in ideal conditions, namely:

• with the use of low-carbon steel plate acting as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with no separation
• with vertical force applied
• at room temperature

Lifting capacity in practice – influencing factors

Practical lifting force is determined by factors, by priority:

• 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 was assessed using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.