29 May 2008
What is the optimal laser for material processing? Jens Bleher, managing director of TRUMPF Laser Technology Division, answers in his own words and explains why TRUMPF needs to offer its customers a complete range of laser technologies.
Which laser beam source will be used predominately for material processing in the future?
We are currently not of the opinion that a "disruptive technology" will appear in the near future. By that I mean a new laser technology that will replace all other beam sources. A broad range of different laser technologies will continue to be used in the future. For this reason, a laser manufacturer needs to be proficient in all types of lasers and be able to offer its customers the relevant technologies.
TRUMPF will continue to develop all varieties of laser technology in order to offer its customers the best laser for every application in material processing. As a result, TRUMPF is the company with the broadest spectrum of sources: CO2, disk, rod and fibre lasers. This is how we differentiate ourselves from the many competitors in the market, some of whom offer only one or two platforms.
Which technology do you see as being out in front? Fibre or disk? CO2 or solid-state?
The wide variety of applications shows that there is no one optimal laser in material processing. Each technology has its strengths that we must use appropriately for the application. Different applications put different requirements on the beam source and on the production system. In our opinion, this is the decisive factor that we must concentrate on.
When do you recommend a disk laser to your customers and when do you recommend a fibre laser?
Higher powers are and will remain the clear domain of the disk laser. It is the right design for industrial applications in the high multi-kilowatt continuous-wave power range. The disk is a robust and easily scalable platform that cost-effectively allows good to very good quality beam generation. It has great potential for the future.
The fibre laser is a good technology primarily for the low power range up to several hundred watts. It is suitable for welding and cutting wherever very precise contours are needed in thin sheet metal. We offer our customers the TruFiber 300 for this purpose. On the other hand, the disk laser also provides enhanced potential if the user wants very short high peak pulse powers.
Why do you categorize the various technologies according to power?
There are applications that one technology can handle better than the other. We have come to this conclusion based on our own knowledge and the application experience of our customers. At this time, we believe that optimal cutting cannot be achieved using a wavelength of 1 µm from a solid-state laser compared with the 10 µm of the CO2 laser for physical reasons. This applies primarily to thicker sheet metal.
The universal cutting machine is currently based on CO2 technology. This also comes from the fact that the cutting experience and process knowledge are considerably greater for the CO2 laser due to decades of use. If the user exclusively wants to cut thin sheet metal and foils, a solid-state laser may be of interest because of the speed advantages.
Why do you offer a cutting system based on a solid-state laser?
We would not be fulfilling our role as a technology leader if we did not also offer cutting systems with a solid-state laser for 2D and 3D applications. We have been doing just that for more than two decades and, in this area, we have a market share exceeding 50%. The customers come primarily from areas that exclusively cut thin sheet metal at a high speed and this is precisely where the solid-state laser can show its benefits.
What requirements should a laser fulfill to allow efficient cutting?
The cutting process must be very robust and the user needs a flexible machine that can be used for all sheet metal – even in small batches. For this reason, a laser cutting system must provide a very broad processing spectrum. In addition, the laser must guarantee high process reliability. However, a sufficiently large cutting gap is also important to allow safe separation of the components.
Does this imply that the only way to be flexible in processing sheet metal is to use a CO2 laser?
It is not quite so simple! The importance of solid-state lasers will grow, also in flexible sheet-metal processing. This is not just for cutting but also primarily for welding. More and more, our customers are viewing laser welding as a cost-effective supplement in the sheet-metal process chain – predominately for joining thin- to medium-thickness sheet metal from 0.6 to 6 mm. In this case, solid-state lasers are appropriate because of their ability to network.
For welding applications requiring high beam quality with powers in the multikilowatt range (for example, in remote welding for the automotive industry or for narrow and deep welds) disk lasers, such as our TruDisk series, are the right concept.
The reasons for this are technical in nature. For the disk laser, in contrast to the fibre laser, the power density inside the resonator remains far below the critical destruction threshold of the laser medium, even at high powers. The disk laser user does not need to fear a beam source failure in the event of reflex reflection from the component because it was designed to be insensitive to reflection. For this reason, the disk laser allows better system utilization and considerably higher productivity.
What technology will lasers be based on in the future?
The key technology of the near future is undoubtedly the diode. Diode-pumped solid-state lasers and direct-diode lasers will play an increasingly important role in our opinion. The diode will become the central element for all lasers. Or, to put it more precisely: it is already!
The crucial factor is to acquire the necessary skills relating to diodes. Important aspects are semiconductor technology and packaging. TRUMPF has been expanding the expertise needed in this area for many years in order to be the technology leader in industrial lasers and laser systems now and in the future.