SM 25x100 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain magnetic properties for almost ten years – the drop is just ~1% (based on simulations),
• They maintain their magnetic properties even under strong external field,
• By using a reflective layer of nickel, the element acquires an proper look,
• Neodymium magnets deliver maximum magnetic induction on a small area, which allows for strong attraction,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to freedom in constructing and the capacity to customize to individual projects,
• Versatile presence in electronics industry – they find application in HDD drives, electric drive systems, precision medical tools, as well as modern systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. 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 power. 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 suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• We suggest casing - magnetic mount, due to difficulties in creating threads inside the magnet and complicated forms.
• 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 magnets are able to complicate diagnosis medical after entering the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what contributes to it?

Holding force of 0 kg is a result of laboratory testing conducted under the following configuration:

• with the contact of a yoke made of low-carbon steel, guaranteeing maximum field concentration
• with a thickness of at least 10 mm
• with a plane cleaned and smooth
• without the slightest air gap between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at ambient temperature approx. 20 degrees Celsius

Determinants of practical lifting force of a magnet

Real force impacted by specific conditions, mainly (from priority):

• Clearance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick plate does not accept the full field, causing part of the power to be lost to the other side.
• Steel grade – the best choice is high-permeability steel. Stainless steels may attract less.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate lowers the holding force.