Quartz glass: L angle after the welding process
Photo: LZH

AUTOMATED JOINING OF COMPLEX GLASS PARTS

Up to now, automated manufacturing of complex glass parts is limited. Scientists of the Glass Group at the Laser Zentrum Hannover e.V. (LZH) have therefore developed a process for the laser-based joining of borosilicate and quartz glass.

Posted 7 May 2014

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In order to achieve a constant quality of the parts, the surface temperature is controlled without contact during the process, and thus, the glass viscosity for joining is reduced in a pre-defined way. Powder filler material is used for bridging the gap. The results of the project show that the new process setup is very well suited for automated manufacturing. The research work was supported by the German Federal Ministry of Economics and Technology.

Laser-based joining of glass parts using powder filler material Photo: LZH

Complex glass parts are, in most cases, manufactured manually by a glass apparatus maker using a gas flame. Since the process cannot be entirely controlled, the quality fluctuates. In order to be able to automate the production of complex parts, e.g. for chemical apparatus engineering, LZH scientists have developed a laser-based process for joining glass parts made of borosilicate and quartz glass. The special feature of the process is an integrated temperature control that regulates the viscosity of the parts in a pre-defined way during the welding process: Here, a CO₂ laser beam source provides the required amount of heat energy. The temperature is measured without contact using a pyrometer.


In order bridge gaps at, for example, L angle geometries, glass powder is added as filler material during the joining process. In doing so, the glass powder is melted and forms a homogeneous welding seam with a constant bead height. The new process setup enables automated joining of glass in various welding configurations, such as butt joints, fillet joints and L angles. The „Research Association Technique and Glass“ (FTG e.V.) submitted the application for the research project titled “laser-based joining of glass parts using powder filler material” (powder joining). The commitment and know-how of the FTG members significantly contributed to the success of the project.		Quartz glass: L angle after the welding process and subsequent laser polishing Photo: LZH

The IGF project no. 17029 N „laser-based joining of glass parts using powder filler material“ of the „Research Association Technique and Glass“ (FTG e.V., Bronnbach 28, 97877 Wertheim, Germany) was supported by the German Federation of Industrial Research Associations (AiF e.V.) within the scope of the Industrial Collective Research Programme (IGF) of the German Federal Ministry of Economics and Technology on the basis of a decision by the German Bundestag.

Laser Zentrum Hannover e.V. (LZH)
As an independent, non-profit research institute, the Laser Zentrum Hannover e.V. (LZH) stands for innovative research, development and consulting. The LZH is supported by the Lower Saxony Ministry for Economics, Labour and Transport and is dedicated to the selfless promotion of applied research in the field of photonics and laser technology. Founded in 1986, over 170 staff have achieved a turnover of 15.993 million euros (for 2013), among others, from income from federal, state, EU and industrial projects.
The focus of the LZH lies on the fields of optical components and systems, optical production technologies, and biomedical photonics. Interdisciplinary cooperation between natural scientists and mechanical engineers makes innovative approaches to challenges from the most different areas possible: from the development of components for specific laser systems to process developments for the most diverse laser applications, for example for medical technology or lightweight construction in the automotive sector. Seventeen spin off companies have emerged from the LZH up to now. Thus, the LZH has created a strong transfer between fundamental science, application oriented research, and industry.

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