Do you have a task where workpieces need to be fixed or transported quickly and easily, or should flaps or doors be kept open or closed?
Do you need to realize high adhesive forces?
Then you cannot avoid the electro holding magnet systems of Schienle Magnettechnik & Elektronik Gmb
HLA DC holding magnet
Holding Magnets are pot magnets and consist of a magnet housing and a DC excited coil.
The magnetic remanence is the remaining residual adhesive force after switching off electro holding magnets.
It is between 20 and 40% of the adhesive force with the device switched on, depending on the workpiece.
This residual force can be overcome with a push-out pin or a foil, thus separating the magnet system.
The adhesive force is the force required to tear off the workpiece from the adhesive surface of the magnet. It can be calculated using Maxwell’s tensile force formula.
The greater the magnetic flux Φ that penetrates the workpiece at a constant adhesive surface, or the greater the magnetic induction B at the adhesive surface, the higher the adhesive force FH.
What influences the air gap the holding force?
The air gap is the mean distance between the holding surface of the magnet and the held workpiece surface. The shape of the surfaces facing each other as well as non-magnetic substances in between (galvanic coatings, lacquer, scale) form its size. The roughness and unevenness of the surface also has the effect of an additional air gap.
The occupancy of the adhesive surface is the contact surface (in %) with which the workpiece rests on the holding magnet. The adhesive force per unit area of a holding magnet is approximately the same over the entire adhesive surface.
The occupancy of the adhesive surface is maximum (100%) when the entire magnetic adhesive surface of the magnet is occupied by the workpiece.
The magnet housing of the holding magnets, which guides the magnetic flux, is made of steel with high permeability.
Therefore, the high adhesive force with anchor plates or workpieces made of steel material is achievable.
However, the actually achievable holding force can be reduced by various application parameters, including lower permeability of the workpiece. Therefore, it depends on the material selection. Also, hardened materials have a lower permeability. As a rule of thumb: The higher the degree of hardness, the lower the magnetic conductivity and thus the achievable holding force.
For each device size, there is an optimal workpiece thickness.
The thickness e.g. of the anchor plate is optimally calculated and designed according to your request.
If the material thickness is chosen too low, the max. adhesive force is not achieved.
A larger than calculated thickness of the anchor plate does not lead to a further increase in the adhesive force.
Holding magnet systems that are needed for clamping or holding workpieces, perform their task mainly in the industries of fixture construction, automation, handling, machine safety. In areas where a long holding time and low energy consumption are discussed, permanent holding magnets are used. These ensure that the load can be reliably held even in the event of a power failure.
Do you have a task where workpieces need to be fixed or transported quickly and easily, or should flaps or doors be kept open or closed?
Please contact us, we are happy to help.
Schienle Magnettechnik + Elektronik GmbH
In Oberwiesen 3 · 88682 Salem-Neufrach
