AM ucho [M12] - magnetic accessories

Pros as well as cons of NdFeB magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• Their magnetic field is maintained, and after approximately ten years it drops only by ~1% (according to research),
• They possess excellent resistance to magnetism drop due to external fields,
• A magnet with a smooth nickel surface is more attractive,
• Neodymium magnets deliver maximum magnetic induction on a contact point, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Possibility of precise forming and optimizing to atypical needs,
• Huge importance in electronics industry – they are utilized in magnetic memories, electromotive mechanisms, medical devices, as well as modern systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 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 immune to moisture, in case of application outdoors
• Limited possibility of making threads in the magnet and complex forms - recommended is a housing - magnet mounting.
• Health risk to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that small components of these magnets can be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Highest magnetic holding force – what it depends on?

Breakaway force was determined for optimal configuration, including:

• with the application of a yoke made of special test steel, ensuring maximum field concentration
• with a thickness of at least 10 mm
• with an ground contact surface
• with direct contact (no paint)
• under axial application of breakaway force (90-degree angle)
• in temp. approx. 20°C

Magnet lifting force in use – key factors

During everyday use, the real power results from many variables, listed from most significant:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick steel causes magnetic saturation, causing part of the flux to be lost into the air.
• Steel grade – ideal substrate is pure iron steel. Hardened steels may have worse magnetic properties.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Rough surfaces reduce efficiency.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. 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 perpendicular forces, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.