SM 25x375 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They do not lose power, even during around ten years – the decrease in lifting capacity is only ~1% (according to tests),
• Neodymium magnets are exceptionally resistant to loss of magnetic properties caused by external magnetic fields,
• In other words, due to the shiny layer of gold, the element looks attractive,
• Magnetic induction on the top side of the magnet is maximum,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Thanks to flexibility in shaping and the capacity to adapt to individual projects,
• Huge importance in electronics industry – they are commonly used in computer drives, brushless drives, medical devices, as well as multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing threads and complex forms in magnets, we recommend using cover - magnetic mechanism.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these products are able to complicate diagnosis 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 increases costs of application in large quantities

Detachment force of the magnet in optimal conditions – what it depends on?

The specified lifting capacity represents the peak performance, measured under optimal environment, namely:

• using a plate made of high-permeability steel, functioning as a circuit closing element
• whose thickness equals approx. 10 mm
• with a surface perfectly flat
• under conditions of ideal adhesion (metal-to-metal)
• under axial application of breakaway force (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in practice – influencing factors

In practice, the actual lifting capacity results from several key aspects, ranked from the most important:

• Distance – existence of foreign body (paint, tape, gap) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is reached only during pulling at a 90° angle. The shear force of the magnet along the surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Material composition – different alloys attracts identically. High carbon content weaken the attraction effect.
• Surface finish – full contact is possible only on polished steel. Rough texture create air cushions, weakening the magnet.
• Temperature – heating the magnet causes a temporary drop of force. 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, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.