Vulcanisation – the secret of long-lasting bonding

The production process of elastomer-bound magnets takes place by vulcanisation, in a vulcanisation mould. Prior to that, the metal part is pre-treated and a so-called rubber compound is made from rubber, ferrite and other materials. These components are placed in the pre-heated vulcanisation mould and vulcanised in hydraulic presses at temperatures of approx. 200° C. By doing so, there is a chemical reaction in the rubber mixture, which is called cross-linking. Here, rubber becomes gum and the physical properties are created. In addition, the result is the chemical connection between gum and metal, which, in its functioning, especially characterise the excellent properties of the pole rings.

In the past, traditional pole rings were made by adhering magnetic materials with a metal part. In doing so, the adhesive bond presents a mechanical weakness. It leads to functional failures because the adhesion is not secure under media and temperature.

In addition, the chemical connection, in connection with the elasticity of the material, creates the basis for safe, simple and inexpensive mounting of the pole rings. Compression connections are realised without any problems due to the careful design of the fit between the shaft and the pole ring. The distension of the pole ring that occurs presents no problem for the magnetic function and resistance over the lifetime.

After moulding and vulcanisation, there is final processing and testing.