UMGW 20x15x7 [M4] GW / N38 - magnetic holder internal thread

Pros as well as cons of NdFeB magnets.

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

• They do not lose power, even during nearly 10 years – the reduction in lifting capacity is only ~1% (theoretically),
• Magnets very well protect themselves against loss of magnetization caused by ambient magnetic noise,
• A magnet with a shiny silver surface is more attractive,
• Magnetic induction on the working layer of the magnet turns out to be strong,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of detailed forming and optimizing to complex requirements,
• Fundamental importance in innovative solutions – they are used in computer drives, brushless drives, precision medical tools, and technologically advanced constructions.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of producing threads in the magnet and complicated forms - preferred is casing - magnet mounting.
• Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets can be problematic in diagnostics medical after entering the body.
• With mass production the cost of neodymium magnets is a challenge,

Best holding force of the magnet in ideal parameters – what affects it?

The specified lifting capacity concerns the maximum value, recorded under ideal test conditions, specifically:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• possessing a massiveness of at least 10 mm to ensure full flux closure
• characterized by smoothness
• with zero gap (no paint)
• during pulling in a direction perpendicular to the mounting surface
• at temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

It is worth knowing that the application force may be lower influenced by the following factors, in order of importance:

• Distance (between the magnet and the plate), since even a very small distance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Loading method – catalog parameter refers to detachment vertically. When attempting to slide, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Metal type – different alloys attracts identically. High carbon content worsen the attraction effect.
• Surface finish – ideal contact is possible only on polished steel. Rough texture create air cushions, weakening the magnet.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was measured with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate lowers the load capacity.