UMGW 36x18x8 [M8] GW / N38 - magnetic holder internal thread

Strengths and weaknesses of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They retain magnetic properties for almost 10 years – the loss is just ~1% (in theory),
• They are noted for resistance to demagnetization induced by external magnetic fields,
• By covering with a lustrous coating of silver, the element presents an elegant look,
• Magnets exhibit excellent magnetic induction on the active area,
• 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...
• Considering the option of precise molding and customization to specialized needs, neodymium magnets can be manufactured in a variety of shapes and sizes, which expands the range of possible applications,
• Fundamental importance in high-tech industry – they are commonly used in magnetic memories, electric motors, diagnostic systems, as well as modern systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in compact constructions

Problematic aspects of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We suggest casing - magnetic mechanism, due to difficulties in producing threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these devices are able to be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum holding power of the magnet – what affects it?

The declared magnet strength refers to the limit force, measured under ideal test conditions, specifically:

• with the application of a yoke made of special test steel, guaranteeing maximum field concentration
• whose thickness equals approx. 10 mm
• with an ideally smooth touching surface
• under conditions of gap-free contact (surface-to-surface)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Determinants of lifting force in real conditions

During everyday use, the real power is determined by many variables, listed from most significant:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Metal type – different alloys attracts identically. High carbon content worsen the interaction with the magnet.
• Surface condition – ground elements guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Thermal environment – heating the magnet causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was measured with the use of a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a minimal clearance {between} the magnet and the plate reduces the holding force.