For the processes used in tool and mold making, the state of the art is manual polishing, which has processing times of often more than 10 min/cm². Therefore, there is a great need, particularly in this industry, for automated polishing processes for complex 3D surfaces. The roughness it requires is often in the range of Ra = 0.05 to 0.3 μm.
On the tool steels 1.2343, 1.2311, 1.2379 and 1.3207, laser polishing can be used to smooth milled and eroded surfaces with a roughness of Ra = 1 to 4 μm down to a roughness of Ra = 0.05 to 0.2 μm. The surface rate here is about 1 cm²/min, but can be increased to up to 10 cm²/min by material-adapted intensity distributions. Injection molding and embossing tools with laser-polished surfaces have comparable service lives to those of manually polished tools.
In addition, when the process parameters are modulated, the gloss level on tool surfaces can be adjusted with high local resolution (150 μm), which also makes it possible to produce two-color and multi-gloss effects. In leather grain, for example, only the recesses of the grain are polished in the tool, the webs remain unprocessed.