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

Advantages and disadvantages of rare earth magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They are noted for resistance to demagnetization induced by external magnetic fields,
• In other words, due to the metallic layer of gold, the element gains visual value,
• Neodymium magnets generate maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Possibility of exact creating as well as adapting to specific applications,
• Wide application in advanced technology sectors – they are utilized in hard drives, brushless drives, medical equipment, and complex engineering applications.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• When exposed to high temperature, neodymium magnets experience 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We recommend cover - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complicated forms.
• Possible danger resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small elements of these devices can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum holding power of the magnet – what affects it?

The declared magnet strength represents the peak performance, recorded under optimal environment, specifically:

• with the use of a sheet made of special test steel, ensuring full magnetic saturation
• with a thickness of at least 10 mm
• with an ground contact surface
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

In practice, the actual holding force depends on many variables, presented from the most important:

• Distance (betwixt the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to paint, rust or debris).
• Loading method – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
• Steel grade – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface condition – ground elements ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.