SM 32x275 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

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

• They retain attractive force for nearly ten years – the drop is just ~1% (according to analyses),
• They show high resistance to demagnetization induced by external field influence,
• By using a smooth layer of gold, the element gains an aesthetic look,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling functioning at temperatures approaching 230°C and above...
• Possibility of detailed shaping as well as adapting to individual conditions,
• Key role in advanced technology sectors – they are used in magnetic memories, electric motors, medical equipment, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as 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 recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Limited possibility of creating nuts in the magnet and complex shapes - preferred is cover - magnetic holder.
• Possible danger to health – tiny shards of magnets can be dangerous, if swallowed, which is particularly important in the context of child health protection. Additionally, small elements of these magnets can disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

Magnet power was defined for ideal contact conditions, including:

• using a plate made of low-carbon steel, serving as a magnetic yoke
• whose transverse dimension equals approx. 10 mm
• with a surface cleaned and smooth
• without the slightest air gap between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

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

• Gap between surfaces – every millimeter of separation (caused e.g. by veneer or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel type – mild steel attracts best. Higher carbon content reduce magnetic properties and holding force.
• Surface quality – the more even the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – temperature increase results in weakening of force. Check the maximum operating temperature for a given model.

* Lifting capacity was assessed using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate reduces the load capacity.