UMGZ 75x34x18 [M10] GZ / N38 - magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They do not lose their magnetism, even after nearly ten years – the reduction of power is only ~1% (based on measurements),
• They remain magnetized despite exposure to magnetic surroundings,
• In other words, due to the shiny nickel coating, the magnet obtains an aesthetic appearance,
• They have very high magnetic induction on the surface of the magnet,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the form),
• With the option for tailored forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Important function in advanced technical fields – they serve a purpose in hard drives, electric motors, diagnostic apparatus as well as high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in compact dimensions, which makes them ideal in compact constructions

Disadvantages of neodymium magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall resistance,
• They lose strength at increased temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is difficult,
• Possible threat related to magnet particles may arise, if ingested accidentally, which is significant in the family environments. Furthermore, small elements from these magnets have the potential to interfere with diagnostics once in the system,
• Due to expensive raw materials, their cost is above average,

Optimal lifting capacity of a neodymium magnet – what affects it?

The given lifting capacity of the magnet corresponds to the maximum lifting force, calculated in the best circumstances, namely:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• under perpendicular detachment force
• under standard ambient temperature

Key elements affecting lifting force

In practice, the holding capacity of a magnet is conditioned by the following aspects, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, since 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 testing was performed on a smooth plate of suitable thickness, under perpendicular forces, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the holding force.