NCM 40x13.5x5 / N38 - channel magnetic holder

Advantages as well as disadvantages of rare earth magnets.

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

• They do not lose magnetism, even after around 10 years – the drop in power is only ~1% (according to tests),
• Neodymium magnets are characterized by exceptionally resistant to demagnetization caused by magnetic disturbances,
• By applying a shiny coating of silver, the element has an professional look,
• Magnets are distinguished by huge magnetic induction on the working surface,
• 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...
• Due to the ability of accurate shaping and customization to individualized solutions, neodymium magnets can be created in a wide range of geometric configurations, which increases their versatility,
• Universal use in advanced technology sectors – they find application in computer drives, electric drive systems, advanced medical instruments, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in miniature devices

Problematic aspects of neodymium magnets and proposals for their use:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in creating nuts and complex forms in magnets, we propose using casing - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The declared magnet strength concerns the maximum value, recorded under optimal environment, namely:

• with the contact of a sheet made of special test steel, guaranteeing maximum field concentration
• possessing a thickness of minimum 10 mm to avoid saturation
• with an ideally smooth touching surface
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• in neutral thermal conditions

Practical aspects of lifting capacity – factors

During everyday use, the real power depends on many variables, presented from the most important:

• Clearance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Base massiveness – too thin steel causes magnetic saturation, causing part of the power to be lost to the other side.
• Metal type – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Surface structure – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal environment – heating the magnet results in weakening of induction. Check the thermal limit for a given model.

* Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.