SM 32x125 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

Besides their remarkable field intensity, neodymium magnets offer the following advantages:

• They do not lose power, even after nearly 10 years – the drop in strength is only ~1% (based on measurements),
• They are resistant to demagnetization induced by external magnetic fields,
• A magnet with a shiny gold surface has an effective appearance,
• Magnets are distinguished by extremely high magnetic induction on the working surface,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of individual modeling and modifying to defined conditions,
• Wide application in advanced technology sectors – they are commonly used in mass storage devices, drive modules, diagnostic systems, and other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a special holder, which not only secures 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 strength 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
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in producing threads and complicated shapes in magnets, we recommend using casing - magnetic holder.
• Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Breakaway strength of the magnet in ideal conditions – what it depends on?

Information about lifting capacity was defined for optimal configuration, taking into account:

• using a plate made of mild steel, serving as a circuit closing element
• with a thickness of at least 10 mm
• with a plane free of scratches
• without the slightest air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at standard ambient temperature

Determinants of practical lifting force of a magnet

Bear in mind that the working load may be lower influenced by the following factors, starting with the most relevant:

• Air gap (betwixt the magnet and the plate), because even a tiny distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick plate does not accept the full field, causing part of the power to be lost into the air.
• Metal type – different alloys attracts identically. Alloy additives weaken the attraction effect.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was measured with the use of a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under attempts to slide the magnet the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.