Laser technology is finding wider and wider use in various industrial applications, but this has not always been the case. Let's take a short "excursion" into history and see how lasers were used in the past and how they are used today.
How does a laser work?
Before the "excursion" itself, it will be good to mention a few words about how the laser actually works. A general schematic of a laser is shown in Figure 1. The basis of a laser is an active medium that is excited in some way (optically, electrically, etc.). The excitation supplies energy to the laser, which is subsequently emitted as a laser beam through a process of stimulated emission. To do this, an optical resonator, which is most often made up of reflective mirrors, must be created.
What makes the laser beam so unique? The uniqueness of this technology lies in the fact that in the process of stimulated emission, the incident and emitted photon have the same energy (frequency), direction, polarization and phase. This important factor gives rise to 3 basic characteristics of the laser that distinguish it from other radiation sources.
A laser beam is:
1) collimated - i.e. it does not collimate
2) monochromatic ("monochromatic") - i.e. the photons generated have the same frequency or wavelength
3) coherent - the generated photons are in phase in time and space
The opposite of a laser is e.g. a classical light bulb, which generates radiation in a completely "chaotic" way and produces photons going in all directions, with different wavelengths and random phase.
It is these revolutionary properties that have made the laser a valuable tool in many different applications. In industry, in particular, the ability to focus the laser beam to a small point and thus achieve the high areal energy density required for materials processing is exploited.
History of the laser
The industrial use of lasers dates back to 1965, when the American Western Electric Company built the first working laser system, which was used to drill diamond cubes. This was followed by a CO 2 laser-based machine for cutting sheet metal in 1967 and a machine for cutting titanium in the early 1970s. Cutting was and still is the most widely used laser technology in industry. Since the 1960s, however, the technology has undergone a major evolution and the laser has found parallel applications in other areas. After the invention of the Nd:YAG solid-state laser, the use in welding was widespread.
As the power of lasers increased over time, new applications emerged, especially in the use of new modern materials. It was possible to achieve higher penetration depths, significantly lower heat affected zones, high productivity, easier automation options, etc.
However, the disadvantage of Nd:YAG lasers was the low beam quality, which was only changed in the evolution of lasers by the fiber laser. The dominant and first industrial pioneer in fiber lasers was IPG Photonics, which has produced more than 40,000 units since 1990. The main advantages over Nd:YAG technology are the high efficiency (35 - 45 %), the service life (up to 100,000 hours), the package size and, last but not least, the low operating costs and almost zero maintenance requirements.
The advent of fibre lasers started the second stage in the evolution of lasers. Current lasers are significantly smaller, more powerful and have a high beam quality of BPP 4 due to their architecture compared to Nd:YAG or CO 2 technologies.
This period has brought a tremendous growth in spatial machining - 2.5D and 3D. The possibility of fiber optic beam guidance, relatively easy integration and the use of a multi-axis manipulator, such as a robot, open up more and more possibilities to use the laser not only for cutting and welding, but also for hardening, welding or even cleaning. Systems complemented by powerful CAD/CAM software give enormous possibilities in trajectory creation, testing without the need to run lasers, detection of potential hazards and the possibility of rapid correction. These modern systems thus bring huge benefits in terms of labour productivity, and in terms of time and personnel savings, make the technology accessible to smaller companies.
It is fair to say that CO 2, diode and disk lasers, which also have substantial industrial applications, have not been lagging behind in their development, but their development has not been as dramatic in the second stage on a global scale.
The current developments in laser technology are particularly focused on diode lasers, which stand out for their conversion efficiency of up to 50 %, low operating and acquisition costs, compactness and excellent beam quality. Already today, fibre lasers are being replaced in the field of metal processing and surface finishing by new diode lasers that are available to medium-sized and smaller companies.
LAO - Industrial Systems, Ltd. has been a reliable partner in the field of laser technology and production improvement for more than 20 years. The laser from LAO with the robot from Stäubli Systems s.r.o. is a company of T M T spol. s r.o. Chrudim together with conveyors, tables and other peripherals integrated into a functional technological unit according to the needs and wishes of the customer. These three companies are currently jointly developing a unified 3D laser robotic application with a wide variability of use. The "Multicell" based cell is a representative example of the cutting-edge implementation of technological know-how and advanced technology for your most demanding needs.
We invite you to the International Engineering Fair 2014 (29 September - 3 October 2014), where you can visit the stand of T M T (Hall A2 ground floor, Stand 20) or Stäubli (Hall G1, Stand 40) to learn more about the "Multicell" laser robotic platform.