Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Successful European Cooperation for Industrial Welding of Lightweight Structures

09.01.2014
The Laser Zentrum Hannover e.V. (LZH) and seven other partners have successfully completed the research project „LaWocs“. From December 2010 to November 2013, the national and international project partners worked intensely on „Laser transmission welding of thermoplastic composite structures“.

Lightweight construction with potential for aircraft, automobiles and ships


Laser welded interior aircraft Pins


Sketch of the process operation

Goals connected with the field of environmental protection are ambitious – and they must be. This includes saving energy by reducing fuel consumption, and related with this, reducing CO2 emissions.

This is a challenge for all industrial manufacturers, from aircraft to automobile to ship construction. In order to achieve these goals, new lightweight construction concepts based on using carbon fiber reinforced plastics (CFRP) or glass fiber reinforced plastics (GFRP) are being developed.

These materials offer not only a high potential for reducing weight, but they also have excellent mechanical properties. Thus, CFRP and GFRP are constantly becoming more and more important for industry. A good understanding of these materials combined with suitable production concepts are thus an important research topic across the globe.

LaWocs: Laser transmission welding of thermoplastic composite structures

In the last three years, the Eurostars project LaWocs „Laser transmission welding of thermoplastic composite structures“ was the first research project to investigate laser based welding of fiber reinforced materials. The goal of the project was to design a project chain from modifying the construction of components to the process, to adapting the material to the process, to optimizing the laser welding process itself.

Up to now, for example, adhesives have been used to join fiber reinforced materials, meaning the material surfaces must be intensively prepared, and a drying stage is necessary. An alternative to adhesives is mechanical joining using rivets or screws. However, this requires holes being drilled in the components, which interrupt the flow of forces along the reinforcing fibers. Laser transmission welding of thermoplastic fiber reinforced materials offers many advantages, including high flexibility, making it possible to weld complicated geometries. Furthermore, laser processing is non-tactile, i.e. forces are not applied to the workpiece.

Also, laser energy can be specifically applied only to places where a welding seam is necessary. Process control can use a non-tactile pyrometer for measuring temperatures, for example to successfully weld thermoplastic GFRP with CFRP. Thus, laser welding of composite materials can be used to simplify production processes. At the same time, this method has a high automation potential, and production with short cycle rates and high piece rates are possible, important pre-requisites for use in industrial manufacturing.

European competency all along the line

European cooperation made it possible to consider all aspects of the individual processing steps for fiber composite workpieces in one research project. Within the framework of the three year joint project, new materials were designed, which are both suitable for laser transmission welding, but still maintain good mechanical properties. Additionally, investigations on a better understanding of the welding process for different thermoplastic materials were carried out, and used for the development of the welding parameters. Thus, the project partners ELEMENT, KVE, EPL, TODS, DEVA, TENCATE, FIBRE and the LZH were able, for the first time, to synergetically implement and optimize all the subprocesses in the material and process development and component construction, including material testing.

The welding process

One of the main goals of the project was the development of a laser based process for welding fiber reinforced composite structures, and belonged to the responsibilities of the scientists in the Composites Group at the LZH. In order to carry out these welding processes, the optical characteristics of thermoplastic materials were used. They are partially transparent in the near infrared spectral range (NIR), and the correct laser radiation can be transmitted through the first welding partner.

The laser radiation is then absorbed by the carbon fibers or the soot particles in the second welding partner, and the electromagnetic radiation is transformed into heat. Due to heat conduction between both welding partners, the respective plastics melt, and a welding seam is formed. The Composites Group has developed, among other things, processes for welding low transparency fiber composite materials, including glass fiber reinforced organic plastic sheets based on a polyetherimide (PEI) structure, which can be welded up to a material thickness of 2.4 mm. Furthermore, processes have been developed to weld thermoplastic angles and braces to components made of formed organic plastic sheets.

Laser welded aircraft pins – a model for the future

Hundreds of thousands of so called aircraft pins are produced yearly for use in wide body aircraft. These pins are an example of the actual components that are in the focus of the LaWocs project. These pins are used for example to connect flooring panels to fire safety equipment and insulation material. Tests have already shown that laser welded pins have a higher strength than pins joined using adhesives, meaning that these pins can be used for weight reduction. Laser transmission welding is thus an excellent solution for fast welding of thermoplastic fiber reinforced materials. Work in this project offer an excellent foundation for the development of an automated process for the industrial manufacturing of these lightweight components, making it a resource efficient, environmentally friendly development in the transportation field.

Project partners:
- DEVA DEVA Kunststoff-Technik GmbH (Germany)
- ELEMENT Element Materials Technology (Great Britain)
- EPL EPL Composite Solutions Ltd (Great Britain)
- Fibre Faserinstitut Bremen e.V. (Germany)
- KVE Kok & Van Engelen Composite Structures BV (the Netherlands)
- LZH Laser Zentrum Hannover e. V. (Germany)
- TENCATE TenCate Advanced Composites BV (the Netherlands)
-TODS Tods Aerospace Limited (Great Britain)
The LZH would like to thank the German Federal Ministry of Education and Research (BMBF) for financial support of the Eurostars project LaWocs (FKZ: 01QE1002D).
Contact:
Laser Zentrum Hannover e.V. (LZH)
Lena Bennefeld
Hollerithallee 8
D-30419 Hannover
Tel.: +49 511 2788-238
Fax: +49 511 2788-100
E-Mail: l.bennefeld@lzh.de
The Laser Zentrum Hannover e.V. (LZH) carries out research and development in the field of laser technology and is supported by the Ministry of Economic Affairs, Labour and Transport of the State of Lower Saxony (Niedersächsisches Ministerium für Wirtschaft, Arbeit und Verkehr).

Michael Botts | Laser Zentrum Hannover e.V.
Further information:
http://www.lzh.de

More articles from Process Engineering:

nachricht Harder 3D-printed tools – Researchers from Dresden introduce new process for hardmetal industry
11.10.2018 | Fraunhofer-Institut für Keramische Technologien und Systeme IKTS

nachricht Flying High with VCSEL Heating
04.10.2018 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Nonstop Tranport of Cargo in Nanomachines

20.11.2018 | Life Sciences

Researchers find social cultures in chimpanzees

20.11.2018 | Life Sciences

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>