Multipolar magnetizing heads

Magnetizing heads

Creating disc or ring magnets

with high pole-pair density

Dimensioning a reliable magnetizing head for production purpose is a delicate task. Indeed, a high magnetic induction must be created in the magnet, which means that high currents have to be generated often in rather small volumes. MMT has acquired a very strong know-how in that field, and more specifically in the production of magnets with high pole-pair density.

The main features of the magnetized parts are:

· High angular pole accuracy

· Axially and radially magnetized ring magnets

· Possible multi-track magnets

· High pole-pair density

· Polar pitch down to 0,5 mm

· Perfect equality between North and South poles => Minimum North/South offset

· Life-time suitable for mass production

Typical magnetization achieved by MMT magnetizing head

MMT magnetizing head for disc magnet

Thanks to the precision and reliability of this method, the magnets can be used either for sensing or actuating purposes.

According to the capabilities of the magnetization bench used to supply the head, any kind of supplying mode (one or several sources) can be implemented by MMT, with the same quality guarantee.

Typical magnetization achieved by MMT linearmulti-track magnetizing head

Basic Principle

Let us consider the cut of a magnetic multipolar structure as shown on the drawing above. The green zones correspond to a copper wire with a positive current, the red ones to a wire with a negative current. When a current peak is applied, a potential difference between the ferromagnetic poles is created and some magnetic flux lines will flow from pole to pole, thus creating a net induction which magnetizes the permanent magnet.

Main applications

MMT is specialized in the design and fabrication of magnetizing heads for production purposes of multipolar permanent magnets with high pole-pair density.

Those magnets are mainly used to get simple, efficient, low cost speed and position digital sensors.

However, our know-how also permits us to design more simple magnetizing devices for sensors or actuators.

The main applications for magnets with high pole-pair density are: