Laser Supported Volume Ablation
Laser engraving is a laser supported, high-volume ablation process, which offers excellent opportunities for making high-precision printing, embossing, erosion, or injection tools. The great advantage over the conventional spark erosion technique consists in the fact that laser engraving is extremely flexible as to geometry and material. In addition, of course, it is free of wear.
The laser engraves the material surface down to some 10 µm in depth. Laser engraved marks are exceptionally durable and can only be removed by heavy grinding. Therefore laser engraving is used for forgery-proof product marking e.g. of ball-bearings.&nb
Repeated scanning of a two-dimensional outline, commonly used with deep marking and trimming, will yield to a 2½ -dimensional ablation with flat bottom and tapered walls. When processing three-dimensional data, walls with defined conicity and bottoms with arbitrary topography can be realized. For the production of micro injection- or forming molds this manufacturing method, based on laser engraving, is entering the market
- Two ablation mechanisms must be differentiated, depending on the applied power density. Low intensities lead to sublimation of the material, with ablation rates of up to 0.5 cubic mm per minute in steel. At higher power densities, the ablation process changes and sublimation-induced fusion displacement takes place. Ablation rates in metal of more than 10 cubic mm per minute can then be achieved. In the case of sublimating materials such as silicon nitrite or graphite, the ablation values can be many times more than this.