NCM 10x13.5x5 / N38 - channel magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent power, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They show superior resistance to demagnetization from outside magnetic sources,
• Thanks to the glossy finish and nickel coating, they have an aesthetic appearance,
• Magnetic induction on the surface of these magnets is notably high,
• Thanks to their enhanced temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• With the option for customized forming and precise design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Wide application in advanced technical fields – they find application in hard drives, rotating machines, healthcare devices along with technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them ideal in miniature devices

Disadvantages of magnetic elements:

• They can break when subjected to a heavy impact. If the magnets are exposed to mechanical hits, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage and strengthens its overall strength,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a humid environment – during outdoor use, we recommend using sealed magnets, such as those made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing holes directly in the magnet,
• Potential hazard due to small fragments may arise, when consumed by mistake, which is crucial in the health of young users. Additionally, miniature parts from these assemblies can complicate medical imaging when ingested,
• Due to the price of neodymium, their cost is relatively high,

Highest magnetic holding force – what affects it?

The given pulling force of the magnet represents the maximum force, measured under optimal conditions, specifically:

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• under perpendicular detachment force
• under standard ambient temperature

Determinants of lifting force in real conditions

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

• Air gap between the magnet and the plate, as 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.

* Lifting capacity was determined using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.