SMZR 25x150 / N52 - magnetic separator with handle

Pros and cons of neodymium magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (according to theory),
• They feature excellent resistance to weakening of magnetic properties due to opposing magnetic fields,
• Thanks to the shiny finish, the coating of nickel, gold, or silver gives an elegant appearance,
• Magnets are distinguished by extremely high magnetic induction on the active area,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to flexibility in forming and the ability to adapt to complex applications,
• Huge importance in electronics industry – they find application in HDD drives, motor assemblies, precision medical tools, also other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 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 immune to moisture, in case of application outdoors
• Due to limitations in creating nuts and complex forms in magnets, we recommend using casing - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the context of child safety. It is also worth noting that small elements of these devices are able to complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price exceeds standard values,

Magnetic strength at its maximum – what contributes to it?

The specified lifting capacity refers to the limit force, measured under optimal environment, namely:

• on a base made of mild steel, optimally conducting the magnetic field
• whose transverse dimension reaches at least 10 mm
• with a plane free of scratches
• without the slightest air gap between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Magnet lifting force in use – key factors

Effective lifting capacity impacted by specific conditions, such as (from priority):

• Clearance – existence of foreign body (paint, dirt, air) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Angle of force application – highest force is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Metal type – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Surface finish – full contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal environment – heating the magnet causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, in contrast under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate lowers the load capacity.