UMGGW 34x8 [M4] GW / N38 - magnetic holder rubber internal thread

Pros and cons of neodymium magnets.

Besides their remarkable field intensity, neodymium magnets offer the following advantages:

• They do not lose magnetism, even during nearly 10 years – the drop in strength is only ~1% (according to tests),
• Magnets perfectly defend themselves against demagnetization caused by external fields,
• In other words, due to the glossy surface of gold, the element looks attractive,
• Magnetic induction on the top side of the magnet is exceptional,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• Possibility of individual forming and optimizing to defined conditions,
• Universal use in modern industrial fields – they serve a role in HDD drives, electromotive mechanisms, diagnostic systems, and multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing nuts and complex forms in magnets, we recommend using casing - magnetic mount.
• Possible danger resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child safety. Additionally, small elements of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Breakaway strength of the magnet in ideal conditions – what it depends on?

Holding force of 7.7 kg is a measurement result performed under specific, ideal conditions:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• possessing a thickness of at least 10 mm to ensure full flux closure
• characterized by even structure
• without the slightest air gap between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• at temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

In practice, the actual holding force is determined by several key aspects, ranked from most significant:

• Air gap (between the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) results in a reduction in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the surface is typically many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Plate material – low-carbon steel gives the best results. Higher carbon content lower magnetic properties and lifting capacity.
• Surface structure – the smoother and more polished the surface, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.