HH 42x8.8 [M6] / N38 - through hole magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is durable, and after approximately ten years, it drops only by ~1% (according to research),
• They protect against demagnetization induced by ambient magnetic fields very well,
• In other words, due to the glossy silver coating, the magnet obtains an professional appearance,
• They possess significant magnetic force measurable at the magnet’s surface,
• Thanks to their enhanced temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• Thanks to the possibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in diverse shapes and sizes, which broadens their functional possibilities,
• Important function in advanced technical fields – they find application in hard drives, electric drives, medical equipment as well as other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which makes them ideal in compact constructions

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to mechanical hits, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks while also strengthens its overall durability,
• They lose strength at increased temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to moisture can corrode. Therefore, for outdoor applications, we suggest waterproof types made of non-metallic composites,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing threads directly in the magnet,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is important in the protection of children. It should also be noted that small elements from these devices may disrupt scanning if inside the body,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum holding power of the magnet – what contributes to it?

The given holding capacity of the magnet represents the highest holding force, determined in ideal conditions, that is:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• under perpendicular detachment force
• in normal thermal conditions

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is conditioned by the following aspects, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, because 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 testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.