UMGGZ 88x8.5 [M8] GZ / N38 - rubber magnetic holder external thread

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• They retain their magnetic properties for around 10 years – the drop is just ~1% (in theory),
• They are highly resistant to demagnetization caused by external field interference,
• In other words, due to the metallic nickel coating, the magnet obtains an stylish appearance,
• They have extremely strong magnetic induction on the surface of the magnet,
• Thanks to their exceptional temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• With the option for fine forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Key role in new technology industries – they are utilized in data storage devices, electric drives, medical equipment as well as technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in tiny dimensions, which allows for use in compact constructions

Disadvantages of neodymium magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to shocks, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall strength,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the dimensions and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a moist environment – during outdoor use, we recommend using waterproof magnets, such as those made of non-metallic materials,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is restricted,
• Safety concern due to small fragments may arise, in case of ingestion, which is significant in the context of child safety. It should also be noted that miniature parts from these products may complicate medical imaging when ingested,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Maximum lifting force for a neodymium magnet – what affects it?

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

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• in conditions of no clearance
• with vertical force applied
• under standard ambient temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet is determined by in practice the following factors, from primary to secondary:

• Air gap between the magnet and the plate, as 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 performed on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate decreases the holding force.