The starting point for manufacturing a CMC watch case is a conventional carbon-fibre reinforced polymer. In a heat treatment called pyrolysis, lasting several days, the polymer matrix is converted to carbon, leaving behind a dense weave of fibres embedded in a porous carbon matrix. Subsequently, silicon crystals are placed on top of the component, and everything is heated in an oven. During this so-called siliconisation, silicon is pulled into the cavities and chemically reacts with the carbon, forming a new matrix made of silicon carbide ceramic.
After finishing with diamond tools, the CMC cases exhibit a matte black colour and a unique structure determined by the fibres, making each piece truly unique. “The manufacturing process for this lightweight and strong material is extremely complex. To achieve perfect quality, we had to overcome countless challenges – from selecting the right raw materials for the fibres and the matrix to defining the exact parameters for the different steps of the process. With its first CMC watch case, IWC again demonstrates its expertise in engineering advanced material solutions,” explains Lorenz Brunner, Department Manager Research and Innovation at IWC Schaffhausen.