UMT 12x20 green / N38 - board holder

Strengths and weaknesses of rare earth magnets.

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

• They do not lose magnetism, even after approximately 10 years – the decrease in lifting capacity is only ~1% (according to tests),
• Magnets perfectly protect themselves against demagnetization caused by ambient magnetic noise,
• A magnet with a metallic gold surface has better aesthetics,
• Magnets exhibit extremely high magnetic induction on the active area,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in constructing and the ability to adapt to complex applications,
• Key role in innovative solutions – they are used in magnetic memories, brushless drives, advanced medical instruments, as well as other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Limited ability of producing nuts in the magnet and complicated shapes - preferred is casing - magnetic holder.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these magnets can disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

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

Holding force of 0 kg is a result of laboratory testing conducted under the following configuration:

• using a base made of mild steel, serving as a circuit closing element
• with a thickness minimum 10 mm
• with a plane free of scratches
• with zero gap (without impurities)
• during pulling in a direction vertical to the plane
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

Please note that the magnet holding will differ depending on elements below, starting with the most relevant:

• Gap (between the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Direction of force – maximum parameter is reached only during perpendicular pulling. The shear force of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is pure iron steel. Cast iron may generate lower lifting capacity.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was determined using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.