NCM 20x13.5x5 / N38 - channel magnetic holder

Pros and cons of neodymium magnets.

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

• Their power is durable, and after around 10 years it decreases only by ~1% (theoretically),
• They retain their magnetic properties even under strong external field,
• A magnet with a metallic gold surface is more attractive,
• Magnets are distinguished by maximum magnetic induction on the surface,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures approaching 230°C and above...
• Due to the option of free molding and adaptation to individualized requirements, NdFeB magnets can be created in a broad palette of shapes and sizes, which expands the range of possible applications,
• Versatile presence in modern technologies – they are utilized in computer drives, motor assemblies, precision medical tools, and complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Problematic aspects of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing threads and complex forms in magnets, we propose using casing - magnetic holder.
• Possible danger related to microscopic parts of magnets pose a threat, in case of ingestion, which is particularly important in the context of child health protection. It is also worth noting that small components of these products are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum lifting force for a neodymium magnet – what it depends on?

The lifting capacity listed is a theoretical maximum value conducted under standard conditions:

• using a sheet made of high-permeability steel, acting as a magnetic yoke
• with a thickness minimum 10 mm
• with an ideally smooth touching surface
• without the slightest clearance between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at room temperature

Key elements affecting lifting force

During everyday use, the real power results from many variables, ranked from most significant:

• Air gap (between the magnet and the plate), because even a microscopic clearance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to paint, corrosion or debris).
• Angle of force application – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin plate does not close the flux, causing part of the flux to be escaped to the other side.
• Metal type – different alloys reacts the same. Alloy additives worsen the interaction with the magnet.
• Smoothness – full contact is obtained only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.