CM PML-10 / N45 - magnetic gripper

Advantages as well as disadvantages of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• Magnets effectively defend themselves against loss of magnetization caused by external fields,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to the potential of accurate forming and customization to specialized projects, magnetic components can be created in a broad palette of forms and dimensions, which amplifies use scope,
• Versatile presence in electronics industry – they are used in magnetic memories, motor assemblies, medical devices, also complex engineering applications.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their power 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 recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• Limited ability of creating nuts in the magnet and complex shapes - recommended is casing - magnetic holder.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the context of child safety. It is also worth noting that small elements of these magnets are able to complicate diagnosis medical after entering the body.
• With mass production the cost of neodymium magnets is a challenge,

Maximum holding power of the magnet – what it depends on?

Breakaway force was defined for ideal contact conditions, assuming:

• with the use of a yoke made of special test steel, guaranteeing maximum field concentration
• possessing a thickness of min. 10 mm to ensure full flux closure
• with an ideally smooth touching surface
• without the slightest clearance between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at room temperature

What influences lifting capacity in practice

Real force is affected by specific conditions, mainly (from most important):

• Clearance – the presence of foreign body (rust, dirt, air) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is usually several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate decreases the lifting capacity.