LIA NEWS


NEWS FROM LIA T


his issue of LSE covers some very interesting current topics including design for laser manufacture, aerospace production, and beam delivery technology


for ultrafast lasers. Design for laser manufacture is an important


step in the chain of laser adoption. It started with just replacing a conventional tool with a laser, as in drilling diamond dies for wire production. Next we add motion and control to make a system. Once the customer understands what the laser system can do then further real benefits come from designing the part for laser manufacture. Benefits include better quality,


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All in the design By Peter Baker, Executive Director, Laser Institute of America


faster production and less wasted material (for example, by making smaller flanges when laser welding). In the case of laser additive manufacturing one aerospace company reported weight savings as high as 80 per cent from proper design. At LIA’s ICALEO conference in October, the


Schawlow Award was presented to Dr Keming Du, of Edge Wave Technology, whose work has led to ultrafast lasers with powers increased from a few watts to hundreds of watts (and more) thereby radically increasing the potential benefits and scale of clean cuts in metal, glass and sapphire.


ABOUT LIA


Laser Institute of America (LIA), founded in 1968, is the professional society for laser applications and safety. Our mission is to foster lasers, laser applications and laser safety worldwide.


www.lia.org


13501 Ingenuity Drive, Ste 128, Orlando, FL 32826, +1 407.380.1553


We wish all Laser System Europe readers a


happy holiday season with even more laser benefits in the New Year!l


Refining weld seams: Reduced ambient pressure improves


solid-state laser performance and reduces spatter By Christian Börner and Klaus Dilger


n the German publicly funded research project LaReD, investigations are conducted to exploit the potential of high


brilliance solid-state lasers and enhance the quality of the joints they produce. Tis project is being carried out at the Institute of Joining and Welding in Braunschweig, Germany, and is supported by the German Welding Society. Te objective is to enable the use


of these modern solid-state lasers for components with the highest requirements on weld seam quality – for example, in gearbox manufacturing for the automotive industry. In this case, a process environment featuring reduced pressure during the welding procedure constitutes the crucial difference when producing high-quality weld seams. To be clear, this is not a vacuum, but only a


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reduced pressure. Te characteristics of the weld quality improvement already occur under a reduced pressure of about 100hPa and are fully completed in a pressure range from 10 to 1hPa.


enable the use of solid- state lasers for components with high requirements on weld seam quality


The objective is to During the laser beam welding


process, local vaporisation occurs in the focus due to the high intensity, which results in the formation of a capillary. Te metal vapour escapes from the keyhole with excessive pressure, which can be seen above the joining area as a bright light. Tis


LASER SYSTEMS EUROPE ISSUE 29 • WINTER 2015


is also called a metal vapour plume (Figure 1). Te bright light of the plume is caused by the temperature radiation of condensed particles in the welding fume. Rising welding fumes and the included particles absorb part of the laser beams. Tis leads to an interaction between the incident laser beam and condensed particles in the welding fume. Te influence on the laser beam due to its interaction with the metal vapour


plume was verified by means of test laser beams. A clear scattering of the visible laser beams onto a target is caused by this interaction. By decreasing the ambient


pressure, the bright light of the plume is clearly reduced. In a pressure range of 10hPa and below, the lightning is practically no longer visible (Figure 1). In addition, an influence by scattering of the visible test laser beam can no longer be


Figure 1. Metal vapour plume depending on ambient pressure @lasersystemsmag | www.lasersystemseurope.com


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