UMH 25x8x45 [M5] / N38 - magnetic holder with hook

Pros and cons of NdFeB magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They do not lose power, even during around ten years – the drop in lifting capacity is only ~1% (theoretically),
• Magnets perfectly defend themselves against demagnetization caused by external fields,
• By using a decorative coating of gold, the element gains an aesthetic look,
• They are known for high magnetic induction at the operating surface, which increases their power,
• 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...
• Possibility of exact modeling as well as adjusting to atypical applications,
• Significant place in electronics industry – they serve a role in data components, electric drive systems, medical equipment, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in compact constructions

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest 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
• We recommend a housing - magnetic holder, due to difficulties in realizing threads inside the magnet and complicated shapes.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these magnets are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Detachment force of the magnet in optimal conditions – what it depends on?

The lifting capacity listed is a theoretical maximum value conducted under the following configuration:

• on a base made of structural steel, perfectly concentrating the magnetic field
• with a cross-section of at least 10 mm
• characterized by lack of roughness
• under conditions of ideal adhesion (surface-to-surface)
• for force applied at a right angle (in the magnet axis)
• at room temperature

Lifting capacity in real conditions – factors

Holding efficiency is influenced by specific conditions, mainly (from most important):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the power to be escaped into the air.
• Metal type – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Plate texture – ground elements ensure maximum contact, which improves force. Uneven metal weaken the grip.
• Temperature – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity was assessed with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet and the plate lowers the holding force.