What affects the strength of a magnet

What does the holding force of magnets mean - What is the holding force of magnets

The holding force of a magnet is a measure of the force that the magnet can exert on a magnetic plate.
It is therefore an essential property of a magnet. It is mainly dependent on the material, the geometry and volume of the magnet, but also on the overall arrangement, e.g. whether the magnet is still in contact with other (magnetic) materials.

Calculation of the holding force of a magnet

The holding force of a magnet can be calculated conditionally with special computer programs, which are based on the F.Use the initen element method (FEM). Such calculations are complicated and cannot simply be unconditionally applied to all geometries.

Measurement of the adhesive force of a magnet

The adhesive force of magnets can be measured by determining the force (using a special digital scale) that is required to pull a magnet vertically from an absolutely flat 10 mm thick iron plate at room temperature.
In order not to falsify the measured value, it is important not to use any metal parts to attach the magnet, but rather to glue it to a wooden or plastic plate, for example.
The description of a precisely defined procedure for measuring the adhesive force of magnets can be found here: Test Method for Determining Breakaway Force of a Magnet

Holding force in Newtons or kilograms

Of course, forces are measured in Newtons (N). The newton is a derived unit and can be represented by the basic units:
1N = 1kg x m / s²
However, since it has become common practice to specify the "strength" of a magnet as the weight that this magnet can hold, we also specify the "holding force" in kg or g. Thus, the specified prison forces apply on earth.

The following applies for the conversion: 1 kg corresponds to a force of 10 N.

Influence on the holding force of a magnet

The adhesive force of a magnet depends on the material of the magnet and its magnetization (e.g. neodymium N45), on its volume, on the geometry, in particular on the aspect ratios and the arrangement of the magnet in relation to the surface of the adhesive.
The calculated adhesive force of a magnet represents a value that is almost achievable in practice at best. For this purpose, the surface of the iron plate adhering to the magnet must be polished and absolutely flat so that there is no distance to the magnet. The same applies to the surface of the magnet itself. If the plate is too thin (compared to the magnet), you will not be able to reach the maximum adhesive force either, since the magnetization of the plate goes into saturation in this case. Coatings of the adhering surface or lacquer also have a negative effect on the adhesive force, as they create a distance between the magnet and the actual metallic adhesive base.
Another very important aspect is the fact that the specified adhesive forces are valid for a force acting perpendicular to the adhesive surface. If you have additional shear forces, as often happens in practice, these also reduce the adhesive force.

What does that mean in practice?

The adhesive forces specified by us in the product descriptions represent realistically achievable values ​​under optimal conditions.
They give a good indication of whether the intended task of the magnet with regard to the adhesive force requirement can be fulfilled.
Ultimately, however, only an application test can clarify whether the selected magnet is suitable for the application.
We therefore urgently recommend this application test of a magnet to every user.