For a long time, the notion of performing structuring and ablation work using solid-state lasers was practically unknown. It is only since micro-processing has been on everyone's mind that these methods are increasingly moving into the spotlight. During laser structuring and laser ablation, workpieces are processed in small and tiny dimensions.
In terms of the methods involved, structuring and ablation are closely related. Short laser pulses with very high pulse power generate such high energy densities that the material usually evaporates immediately (sublimates). This method creates only a minimal melt. Each laser pulse produces a small depression, typically measuring approx. 10 micrometers in diameter and just a few micrometers in depth.
The term 'structuring' refers to the process of generating regular geometries in a surface in order to selectively modify its technical properties. The individual elements in such structures often measure only a few micrometers.
Ablation is mostly used in tool and mold making, and in the electronics and semi-conductor engineering sectors. In injection molding tools, for example, lasers generate highly detailed three-dimensional depressions. These shapes are then adopted by the plastic part later on during the injection molding phase. However, lasers can also selectively ablate thin layers, for example for trimming resistors or for marking components.
A distinction is made between percussion, trepanning, and helical drilling. During percussion drilling, the laser's focus remains fixed in one spot. With trepanning drilling, a start hole is first drilled using several laser pulses. The hole is then enlarged by moving the laser's focus in a circular motion in the hole. During helical drilling, numerous laser pulses work down to the necessary depth in a circular motion, like a spiral staircase.