MW 5x4 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

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

• They have stable power, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• A magnet with a shiny gold surface looks better,
• Neodymium magnets achieve maximum magnetic induction on a small area, which allows for strong attraction,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Possibility of custom modeling and modifying to defined requirements,
• Universal use in electronics industry – they find application in HDD drives, electric motors, medical devices, and multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting 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 suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We recommend a housing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex forms.
• Potential hazard to health – tiny shards of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that tiny parts of these magnets are able to disrupt the diagnostic process medical after entering the body.
• With mass production the cost of neodymium magnets is economically unviable,

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

Holding force of 1.11 kg is a measurement result performed under standard conditions:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• whose thickness reaches at least 10 mm
• with a surface perfectly flat
• with zero gap (without coatings)
• under axial force vector (90-degree angle)
• at room temperature

Key elements affecting lifting force

Real force is affected by working environment parameters, such as (from priority):

• Distance (between the magnet and the plate), as even a very small clearance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Direction of force – highest force is available only during pulling at a 90° angle. The shear force of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin steel does not accept the full field, causing part of the power to be wasted to the other side.
• Steel type – low-carbon steel gives the best results. Alloy steels decrease magnetic permeability and holding force.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity was measured with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.