UMGZ 20x15x7 [M4] GZ / N38 - magnetic holder external thread

Strengths as well as weaknesses of neodymium magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• They retain full power for around ten years – the loss is just ~1% (in theory),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• The use of an refined finish of noble metals (nickel, gold, silver) causes the element to look better,
• Magnetic induction on the working part of the magnet is maximum,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Due to the potential of flexible molding and customization to unique solutions, NdFeB magnets can be produced in a wide range of geometric configurations, which increases their versatility,
• Key role in advanced technology sectors – they are commonly used in hard drives, brushless drives, medical equipment, also multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which makes them useful in miniature devices

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic holder, due to difficulties in producing nuts inside the magnet and complex forms.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. Additionally, small components of these devices can be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

The load parameter shown refers to the maximum value, measured under ideal test conditions, meaning:

• on a base made of mild steel, effectively closing the magnetic field
• possessing a massiveness of min. 10 mm to ensure full flux closure
• with an ideally smooth contact surface
• with direct contact (no paint)
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Lifting capacity in real conditions – factors

During everyday use, the real power depends on several key aspects, listed from crucial:

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin steel does not close the flux, causing part of the flux to be wasted into the air.
• Material composition – different alloys reacts the same. High carbon content weaken the attraction effect.
• Surface finish – ideal contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.