CM PML-10 / N45 - magnetic gripper

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They do not lose their even during nearly ten years – the reduction of lifting capacity is only ~1% (according to tests),
• They show exceptional resistance to demagnetization from external field exposure,
• In other words, due to the metallic silver coating, the magnet obtains an professional appearance,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• With the option for fine forming and targeted design, these magnets can be produced in multiple shapes and sizes, greatly improving application potential,
• Significant impact in new technology industries – they find application in computer drives, electric motors, healthcare devices or even other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and increases its overall resistance,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a humid environment, especially when used outside, we recommend using waterproof magnets, such as those made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing fine shapes directly in the magnet,
• Safety concern related to magnet particles may arise, if ingested accidentally, which is important in the family environments. Moreover, minuscule fragments from these devices can disrupt scanning once in the system,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Maximum lifting capacity of the magnet – what it depends on?

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

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• under standard ambient temperature

Magnet lifting force in use – key factors

In practice, the holding capacity of a magnet is affected by these factors, arranged from the most important to the least relevant:

• 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 measured with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate lowers the holding force.