Microprocessing

Structuring and ablation are closely related processes. Short laser pulses of extremely high power produce an energy density so high that the material practically vaporizes without passing through a liquid phase (it sublimates). Very little molten material results from this process. Each laser pulse produces a small depression that is typically 10, 20, or more micrometers in diameter and only a few micrometers deep.
Laser structured solar cell.

For a long time, very few people had ever heard of structuring and ablation with solid -state lasers. The rise in the popularity of microprocessing, however, has focused more attention on these processes. The reason for this is simple: both processes make it possible to machine workpieces in small and ultrasmall dimensions.

Structuring

produces uniformly arranged geometries in surfaces with the goal of inducing specific changes to the surface’s technical properties. In such structures, one single element often measures only a few micrometers.

Laser ablation

is usually used in the manufacture of tools and molds as well as in electronics and semiconductor technology. In injection molding, for example, lasers produce highly detailed, three -dimensional molds into which resin is injected for creating plastic parts. The laser, however, can also be used to trim resistors or mark parts by selectively removing thin layers of material.

Drilling

At percussion drilling multiple laser pulses "peck" at the workpiece, producing the hole little by little. Producing a pilot hole, that is then enlarged in a series of circular motions is called trepanning. Helical drilling means that many laser pulses work their way into the workpiece in a downward spiral.

Laser cutting and laser drilling

Laser cutting and laser drilling

The laser can handle a variety of cutting tasks.
These range from micrometer-precise cutting joints in paper-thin semiconductor chips to quality cuts in 30-millimeter-thick steel. In laser drilling, the laser beam generates very small to large holes in metals, plastics, paper and stone, without contact.
Principle of laser cutting.

Where the focused laser beam strikes the workpiece, it heats the material so extremely that it melts or even vaporizes. Once it has completely penetrated the workpiece, the cutting process can start: the laser beam moves along the part contour, melting the material as it goes. Usually, a stream of gas blows the melted material downwards, out of the cut. The gap is barely wider than the focused laser beam itself.

In laser drilling, a short laser pulse melts and vaporizes the material with a high power density.
The resulting high pressure drives the molten material out of the hole.

Laser welding and laser soldering

Laser welding and laser soldering

The laser beam provides a variety of ways to join metals: it can join workpieces at the surface or produce deep welds. It can be combined with conventional welding methods and, additionally, be used for soldering.
Laserschweißen von Dickblech.
Even when seam welding with continuous laser beams, the heat-affected zones and the complete heating of the component are still considerably less than with arc or plasma welding. The supply of energy can be well monitored, regulated and maintained or precisely controlled.

Materials with a high melting point as well as high heat conductivity can be welded using a laser. Due to the small amount of molten material and the short, controllable melting period, some materials can be combined, which otherwise could not be welded. Filler materials can be used, if needed. Even when seam welding with continuous laser beams, the heat-affected zones and the complete heating of the component are still considerably less than with arc or plasma welding. The supply of energy can be well monitored, regulated and maintained or precisely controlled.
In soldering, the mating parts are joined by a filler material, or solder. The surface of the solder seam is smooth and clean, forming a nicely curved transition to the workpiece. Since solder seams do not require finishing, they are often used in the automotive industry for making body parts such as trunk lids or car roofs.