1. PCD – total thickness 1.6mm
The sample supplied was from the edge of a mother disc. A cut was made radially. (The reduction in PCD layer thickness near the edge of the disc is visible). The cut with the wet laser is silver in colour on the carbide (a wire cut flank is usually ‘gold’ coloured from the brass wire used). The cut with the LMJ was made from the PCD side down into the PCD layer and then into the carbide layer.
Below left: the left side of the PCD has been cut by the LMJ wet laser. The right hand side was wire cut. In particular, one can see that a chip free edge has been produced by the wet laser.
Above right: at 100x the perfection of the wet laser cut edge on the left is very clear to see. On the wire cut (right) flank one can see the preferential erosion at the interface between the PCD layer and the carbide substrate. This is because the interface here has a higher cobalt content and so is more electrically conducting. The LMJ cut flank is smooth and continuous – there is no step or trench at the interface.