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

Pros and cons of rare earth magnets.

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

• They do not lose strength, even during around ten years – the drop in strength is only ~1% (according to tests),
• Neodymium magnets are characterized by remarkably resistant to loss of magnetic properties caused by external field sources,
• By using a decorative layer of silver, the element acquires an aesthetic look,
• Magnets are distinguished by extremely high magnetic induction on the outer layer,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to versatility in shaping and the ability to customize to complex applications,
• Huge importance in future technologies – they find application in data components, electric motors, medical devices, also technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Problematic aspects of neodymium magnets and ways of using them

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of producing threads in the magnet and complex shapes - preferred is a housing - magnetic holder.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that small elements of these devices can complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The force parameter is a result of laboratory testing performed under the following configuration:

• on a block made of mild steel, effectively closing the magnetic flux
• whose thickness is min. 10 mm
• with an polished contact surface
• without the slightest air gap between the magnet and steel
• under vertical force direction (90-degree angle)
• at standard ambient temperature

Lifting capacity in practice – influencing factors

Bear in mind that the working load will differ depending on the following factors, in order of importance:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material type – the best choice is pure iron steel. Hardened steels may generate lower lifting capacity.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Thermal environment – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.