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

Pros and cons of NdFeB magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (according to literature),
• Magnets effectively resist against demagnetization caused by foreign field sources,
• Thanks to the reflective finish, the plating of nickel, gold, or silver gives an elegant appearance,
• They are known for high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Possibility of accurate forming and modifying to concrete requirements,
• Key role in innovative solutions – they are utilized in mass storage devices, electric drive systems, medical equipment, as well as multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their strength 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 - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of making threads in the magnet and complicated forms - recommended is casing - magnetic holder.
• Possible danger resulting from small fragments of magnets are risky, if swallowed, which becomes key in the context of child safety. It is also worth noting that small elements of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is a challenge,

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

Holding force of 25 kg is a measurement result conducted under the following configuration:

• using a base made of low-carbon steel, acting as a circuit closing element
• possessing a thickness of at least 10 mm to avoid saturation
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• under axial force direction (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in real conditions – factors

In practice, the real power results from many variables, presented from most significant:

• Gap between surfaces – every millimeter of separation (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Direction of force – maximum parameter is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is standardly many times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin steel does not close the flux, causing part of the flux to be escaped to the other side.
• Material type – the best choice is pure iron steel. Cast iron may have worse magnetic properties.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Temperature – heating the magnet results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under attempts to slide the magnet the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.