What makes the laser so remarkable?
Laser is an acronym and stands for “Light Amplification by Stimulated Emission of Radiation.” In 1917, Albert Einstein described the principle of stimulated emission and thus created the theoretical basis that remains valid to this day. However, the first laser was only built decades later. In 1960, Theodore H. Maimann introduced his ruby laser. Lasers were first used as cutting tools in the early 70s, integrated into existing machines.
To understand this tool, one must know the properties of laser light. In and of itself, a laser beam cannot do anything. Only when it is guided, shaped and bundled does it become a tool.
Its particular properties make this so:
- Laser light is monochromatic.
- That means that all the light waves have the same wavelength.
- In a laser beam, all light waves are vibrating at the same frequency.
- This is called coherence.
- The light waves run practically parallel to each other.
- Therefore, the laser beam only widens to a very small extent.
- The power density of the laser beam is much higher than that of the usual light source.
The power density in the laser beam can exhibit various structures.
This internal structure is designated with the English term mode.
The power of the laser beam usually used for cutting is concentrated in the center of the cross-section and decreases toward the edges (Gaussian distribution).
Up to the present, the laser has had competition. But in comparison to all other cutting processes, it offers decided advantages:
- Lasers work touch-free.
- Whereas in other sheet processing methods massive tools are applied to the material with enormous mechanical forces, a laser beam does its cutting work without touching anything.
- The light waves are absorbed by the material and transformed into heat.
- The sheet becomes hot, and melts, evaporates or burns.
- The workpiece does not experience a mechanical load.
- The laser beam does not wear out like other tools.
- Lasers work precisely.
- They can produce fine contours and structures with great precision.
- Lasers only heat the material locally.
- The heated zone is very small.
- The rest of the workpiece receives little or no heat.
- Lasers are flexible.
- A single tool permits the formation of very different forms and contours.
Different processes can be carried out by a single machine. For instance, sheet metal parts can be cut out and immediately labeled.
Cost efficiency and quality are the determining factors in deciding for or against laser processing.
The advantages of laser processing must be balanced against high investment costs:
the laser device and the machine it is part of cost more than conventional machines.
The laser makes up for this drawback with the following strong points:
- Lasers are fast.
- The process speed is often greater than with conventional processes.
- Higher productivity compensates for the high investment costs.
- Lasers deliver quality.
- The quality of laser processing is often better than that of conventional processes.
- Lasers cut down on secondary work or make it superfluous. This speeds up production and increases productivity.