Date: 2018-02-27 14:30
A primary forming process that allows complex three-dimensional surface structures to be achieved with a high degree of precision.
As a primary forming process, electroforming starts with the production of a primary form – similar to the production of a gold mould for series jewellery production.
The most finely structured complex primary forms can be created – especially with the aid of modern laser technology.
The process enables the surface structure of the primary form to be produced with nanometre precision.
The respective number of plastic negative forms are derived from this primary form for producing the final product. This is achieved, for example, by using a plastic-injection-moulding process, whereby the primary form acts as a tool. While a complex production process used to be required to create the surface of the primary form, much less effort is now needed compared to original manufacture to reproduce expendable moulds. At 655 to 755 nanometres, the precision lost from turning the primary form into negative production forms is well below visually recognisable variations.
A major advantage of this process is thus the fact that there is no noticeable loss.
A thin film is applied – for example, using a PVD process – to the surface of the plastic negative form, making it conductive.
Electroplating is then used. The now conductive plastic forms are used as an anode in an electroplating process, whereby the cathode material (. copper) separates from the surface of the plastic forms, slowly replenishing the negative form. The separated material thus becomes the final product.
The relief-forming composition of the final product produced during the electroplating process also faithfully renders the micro surface structure of the forms. Highly precise, metallic copies of the primary form are ultimately created from the cathode material.
Lastly, the plastic forms are then dissolved in chemicals and thus lost in the production process. The final product of the process is thus released. Decorative coatings can be applied to give the product a final finish.
The process is ideal for producing complex, finely structured relief dials. Above all, this offers the freedom to produce small partial areas with completely different micro surface properties, as the usual restrictions when using mechanical tools no longer apply.
The relief dial on our 6796 Heimat model was produced using the process described above. It thus exhibits highly defined details and differently structured detailed surfaces ranging from matt silk to polished. The final finish comes in the form of a thin layer of rhodium.