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

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They retain their attractive force for around ten years – the drop is just ~1% (according to analyses),
• They protect against demagnetization induced by surrounding magnetic fields very well,
• The use of a decorative nickel surface provides a refined finish,
• Magnetic induction on the surface of these magnets is impressively powerful,
• With the right combination of compounds, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the design),
• The ability for accurate shaping or customization to custom needs – neodymium magnets can be manufactured in many forms and dimensions, which extends the scope of their use cases,
• Key role in new technology industries – they are utilized in computer drives, electric motors, healthcare devices and high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which allows for use in compact constructions

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to physical collisions, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage and strengthens its overall durability,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is wise to use sealed magnets made of rubber for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing threads directly in the magnet,
• Health risk linked to microscopic shards may arise, especially if swallowed, which is notable in the context of child safety. It should also be noted that tiny components from these products have the potential to complicate medical imaging when ingested,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Maximum lifting capacity of the magnet – what contributes to it?

The given lifting capacity of the magnet means the maximum lifting force, calculated under optimal conditions, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Determinants of practical lifting force of a magnet

The lifting capacity of a magnet is influenced by in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

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