Cold, non-destructive cutting:
Ultrashort pulse lasers and other trends
at LASER World 2013
Extremely high power, but with extremely short pulse durations - thanks to this combination, ultrashort pulse lasers have been conquering entirely new applications in manufacturing and medicine for several years now. LASER World of PHOTONICS, the leading international trade fair that takes place at the Messe München trade-fair center from May 13 - 16, 2013, will demonstrate that, while laser pulses continue to get shorter, their power is increasing. Visitors will discover the latest capabilities at the scientific World of Photonics Congress, which takes place at the neighboring ICM - International Congress Center München from May 12 - 16, 2013 and features six conferences with more than 2,500 presentations under a single roof.
The laser's capabilities have been fascinating users ever since it was invented: It is extremely precise, uses extremely strong bundled energy, and it is ideally suited for the extremely delicate tasks that it performs. But there is one problem: Heat can damage or destroy materials and tissue to an extent that was no longer acceptable and limited potential applications - until the ultrashort pulse laser was developed. It sends pulses of just a few picoseconds or less into the material. As a result, it can be used to cut into or remove material before enough heat is generated to damage it.
"The products on the market - at least those in the picosecond-laser range - are now suitable for industrial use and are being used in three-shift manufacturing," explains Christof Siebert, Senior Manager for Microprocessing Applications at Trumpf Laser- und Systemtechnik. The laser expert is chairing an Application Panel on the "Latest Applications for Shortpulse Laser Systems". The session takes place at the Forum in Hall C2 on May 13 (14:00 - 16:00).
The ongoing development of ultrashort pulse lasers is an important aspect of the exhibition sector for "Lasers and Laser Systems for Production Engineering" (Halls C1 and C2) and a topic of discussion at the "Lasers in Manufacturing 2013" (LIM) conference, which is part of the World of Photonics Congress at the ICM.
pulses and higher average power
According to Siebert, "the current trend is toward increasing average power as a way to optimize productivity and efficiency. The second is toward lasers that are suitable for industrial use with increasingly shorter pulse durations in order to expand the range of materials in cold processing to include more sensitive materials than in the past."
For Dr. Arnold Gillner, Head of the Department for Material Removal and Joining at the Fraunhofer Institute for Laser Technology, the trend is toward higher average power in the 500 W range. "At the Fraunhofer ILT, a prototype of a 1-kW femtosecond laser has already been demonstrated," adds Gillner, who will lead the panel on ultrashort pulse lasers with Siebert. For the scientists, the key question is how to apply the higher average power of USP lasers to the workpiece and achieve high ablation quality." The Fraunhofer ILT will introduce two approaches to doing so at the fair: An ultra-fast scanning system with beam-deflection speeds greater than 300 m/s, and a multiple-beam optics system to parallelize processing by more than two orders of magnitude.
Besides technical feasibility, naturally costs play a large role in these recent developments. One of the objectives of the experts at Jenoptik, for example, is to use higher power and the resulting increased productivity to offset the costs of investing in femtosecond lasers. When it comes to performance reliability, femtosecond lasers are now delivering "very good application results in full-time, 24/7 operation." Jenoptik, for example, increased the pulse-repetition rate of its D2.fs femtosecond disk laser to more than 500 kHz and improved its output power by 25 percent. Jenoptik is also using a new series of lenses to round out its range of all-quartz lenses for high laser power.
materials without delamination
According to Dr. Gyu C. Cho, Executive Vice President of ultrashort pulse fiber-laser pioneer IMRA, the application fields in which ultrashort pulse lasers can put their strengths to full use include precision processing of transparent materials and extremely hard, brittle materials. Due to these systems, Dr. Cho also sees completely new possibilities when it comes to cutting composite materials would burn or delaminate on the edges if classic lasers or other methods were used. IMRA manufactures femtosecond lasers for a variety of applications with an average power of up to 20 W and a pulse energy of 50 microjoules. According to Dr. Cho, the first industries that will profit greatly from ultrashort pulse lasers include display manufacturing as well as the semiconductor and microelectronics industry.
Ultrashort laser pulses can definitely be used differently on glass or brittle materials. Increasingly thinner and harder glass touchscreens on Smartphones are a good example: "Picosecond lasers like the TruMicro Series 5000 are ideal for cutting the glass plates. This technique avoids microcracks that appear when diamond saws or continuous or long-pulse lasers are used", says Trumpf expert Christof Siebert, explaining the benefits.
Using USP lasers
in medicine also on the rise
This technology also offers great advantages in medicine and medical technology. The most important trend in medicine "is the use of ultrashort pulse lasers in laser refractive cataract surgery (LRCS)", explains Dr. Matthias Schulze, Marketing Director at Coherent. This has been the most rapidly growing application for lasers in medicine in the last one to two years. The technology permits "even better vision when replacing the intra-ocular lens (IOL) in cataract surgery," says Schulze. For example, it makes it possible to better prepare the eye for the use of premium IOLs by using precision cuts to correct astigmatism. His forecast for the future: "Compact lasers will make it possible to use smaller treatment stations, and higher pulse rates will make operation times even shorter."
Users often know too
little about the technology's benefits
A market study that the Munster-based technology consulting firm LOTSE conducted for the Rostock Welding and Research Institute at the MIKROLAS Innovation Forum demonstrated how important it is for manufacturers and users to exchange ideas and information at the fair. One result: Ultrashort pulse lasers can predominantly be found in scientific laboratories and development environments. "At present, the only market applications that are worth mentioning are in the picosecond range," reports Dr. Josef Gochermann, Managing Director of LOTSE. The major reason is a lack of information: "Potential future users of ultrashort pulse technologies still know too little about the possible uses of this technology and the benefits that they can expect for their specific applications," explains Gochermann.
The international trade fair LASER World of PHONTONICS and the World of Photonics Congress, which features information on the latest developments and potential uses of USP lasers under a single roof, can give them an information edge.
LASER World of PHOTONICS 2013
from 13 to 16 May 2013, Fair ground Munich (Germany)
Images: R. Eberhard, messekompakt, EBERHARD print & medien agentur gmbh
Quelle: Messe Munich