JM 15x40 - jajka w pudełku/cena za parę - magnetic eggs

Pros as well as cons of rare earth magnets.

Besides their remarkable field intensity, neodymium magnets offer the following advantages:

• They retain magnetic properties for almost ten years – the loss is just ~1% (based on simulations),
• They retain their magnetic properties even under external field action,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Neodymium magnets deliver maximum magnetic induction on a small area, which allows for strong attraction,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for operation at temperatures reaching 230°C and above...
• Possibility of individual creating as well as adjusting to specific needs,
• Wide application in innovative solutions – they are used in hard drives, electromotive mechanisms, precision medical tools, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which allows their use in compact constructions

Cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic mechanism, due to difficulties in producing threads inside the magnet and complicated forms.
• Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the context of child safety. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what it depends on?

The force parameter is a measurement result conducted under specific, ideal conditions:

• using a base made of low-carbon steel, serving as a circuit closing element
• whose transverse dimension equals approx. 10 mm
• with a plane cleaned and smooth
• with zero gap (no impurities)
• for force acting at a right angle (in the magnet axis)
• at temperature room level

Magnet lifting force in use – key factors

Effective lifting capacity impacted by working environment parameters, such as (from most important):

• Clearance – the presence of any layer (paint, dirt, air) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Stainless steels may attract less.
• Surface finish – full contact is possible only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate reduces the load capacity.