SM 32x425 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

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

• They retain full power for nearly 10 years – the drop is just ~1% (according to analyses),
• They have excellent resistance to magnetic field loss as a result of external magnetic sources,
• A magnet with a shiny nickel surface has an effective appearance,
• Magnetic induction on the surface of the magnet turns out to be very high,
• 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...
• Possibility of individual machining and adjusting to defined conditions,
• Significant place in modern industrial fields – they are commonly used in hard drives, electric motors, precision medical tools, also industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• At very strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures 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 suggest cover - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex forms.
• Health risk related to microscopic parts of magnets are risky, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, tiny parts of these devices are able to disrupt the diagnostic process 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 hinders application in large quantities

Magnetic strength at its maximum – what affects it?

Information about lifting capacity is the result of a measurement for optimal configuration, including:

• using a sheet made of mild steel, functioning as a magnetic yoke
• whose thickness is min. 10 mm
• with a plane free of scratches
• with direct contact (without paint)
• under vertical force direction (90-degree angle)
• in neutral thermal conditions

Determinants of lifting force in real conditions

Effective lifting capacity impacted by specific conditions, including (from most important):

• Gap (between the magnet and the plate), because even a very small distance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Load vector – maximum parameter is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Metal type – different alloys reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface finish – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – hot environment reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the holding force.