MW 8x20 / N38 - cylindrical magnet

Advantages as well as disadvantages of rare earth magnets.

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

• Their power is durable, and after around 10 years it decreases only by ~1% (according to research),
• Magnets effectively protect themselves against demagnetization caused by external fields,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• Neodymium magnets generate maximum magnetic induction on a contact point, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to modularity in constructing and the ability to modify to complex applications,
• Significant place in modern industrial fields – they find application in mass storage devices, electric motors, medical equipment, as well as complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• 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.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Due to limitations in producing nuts and complicated forms in magnets, we recommend using casing - magnetic holder.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that tiny parts of these devices can complicate diagnosis medical after entering the body.
• Due to neodymium price, their price is higher than average,

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

Information about lifting capacity is the result of a measurement for the most favorable conditions, taking into account:

• with the contact of a yoke made of low-carbon steel, ensuring full magnetic saturation
• possessing a massiveness of at least 10 mm to avoid saturation
• characterized by lack of roughness
• without any insulating layer between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

In real-world applications, the real power is determined by a number of factors, ranked from most significant:

• Gap (betwixt the magnet and the metal), since even a microscopic distance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to paint, rust or dirt).
• Load vector – highest force is obtained only during perpendicular pulling. The force required to slide of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin plate does not accept the full field, causing part of the flux to be lost to the other side.
• Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Temperature – temperature increase 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 the force acted perpendicularly, in contrast under parallel forces the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.