CM PML-3 / N45 - magnetic gripper

Strengths as well as weaknesses of neodymium magnets.

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

• They retain magnetic properties for nearly 10 years – the loss is just ~1% (according to analyses),
• They retain their magnetic properties even under strong external field,
• Thanks to the reflective finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an aesthetic appearance,
• Magnets possess maximum magnetic induction on the outer side,
• 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 detailed forming as well as adapting to defined needs,
• Huge importance in modern technologies – they are utilized in mass storage devices, drive modules, medical devices, and complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets and proposals for their use:

• At strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in creating threads and complicated forms in magnets, we recommend using a housing - magnetic holder.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child safety. It is also worth noting that small components of these products can disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

Breakaway force is the result of a measurement for optimal configuration, including:

• using a sheet made of high-permeability steel, serving as a circuit closing element
• possessing a thickness of min. 10 mm to avoid saturation
• with a surface perfectly flat
• with direct contact (without impurities)
• under perpendicular force vector (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in practice – influencing factors

In practice, the actual lifting capacity is determined by a number of factors, listed from crucial:

• Gap (between the magnet and the plate), as even a very small clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Loading method – catalog parameter refers to pulling vertically. When slipping, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Steel thickness – too thin sheet does not accept the full field, causing part of the power to be wasted into the air.
• Material composition – not every steel reacts the same. High carbon content weaken the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.