NCM 40x13.5x5 / N38 - channel magnetic holder

Pros and cons of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They do not lose power, even after nearly 10 years – the decrease in power is only ~1% (based on measurements),
• They are extremely resistant to demagnetization induced by external magnetic fields,
• Thanks to the shimmering finish, the plating of Ni-Cu-Ni, gold-plated, or silver-plated gives an clean appearance,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to freedom in constructing and the ability to modify to client solutions,
• Huge importance in innovative solutions – they find application in computer drives, electric drive systems, diagnostic systems, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power 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 recommend using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic mount, due to difficulties in creating nuts inside the magnet and complex shapes.
• Health risk related to microscopic parts of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical when they are in the body.
• Due to neodymium price, their price is higher than average,

Maximum magnetic pulling force – what affects it?

The declared magnet strength refers to the peak performance, obtained under laboratory conditions, meaning:

• using a plate made of mild steel, functioning as a ideal flux conductor
• whose transverse dimension reaches at least 10 mm
• with a plane free of scratches
• under conditions of gap-free contact (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at temperature room level

What influences lifting capacity in practice

It is worth knowing that the working load will differ influenced by elements below, starting with the most relevant:

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Cast iron may attract less.
• Smoothness – full contact is possible only on smooth steel. Rough texture create air cushions, reducing force.
• Temperature – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.