CSIR develops new laser welding method developed for Denel rocket motor casings

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Denel and the Centre for Scientific and Industrial Research’s National Laser Centre are collaborating on the use of laser welding in the manufacturing of rocket motor casings for the state arms company’s A- Darter short-range air-to-air missile project.
Denel and a Brazilian partner are currently developing the A Darter for the South African and Brazilian air forces in an R1 billion collaborative venture called Project Assegaai by the SA Air Force.     
The CSIR`s latest newsletter says Corney van Rooyen, a metallurgical and welding engineer at the National Laser Centre and colleague Herman Rossouw, an electronic engineer, have developed a “unique solution to the welding process after it was found that very high levels of robot manipulation skills and concentration were required when the welding was done manually.
“Any lapses in concentration could damage equipment, the customer’s product and more significantly, injure the operators. It was also clear that the manual process would not be able to cope with the total production volume of 100 units,” the newsletter said.
Van Rooyen says his team has succeeded in developing a camera-based system that allows the correct positioning of the welding robot by simply pointing a mouse-driven cursor at the desired position displayed on a computer screen.
“This means that from a situation where only highly-skilled robot operators could perform the process, other trained operators can now do it with confidence and without posing any risks to equipment or themselves,” he says.
“What is equally significant about this invention it that this was achieved in a few weeks and at a fraction of the price of a commercial equivalent.”
The venture has been in a trial phase since 2005 but has now been formalised after the CSIR National Laser Centre proved the effectiveness of its welding expertise.
The newsletter notes this involved the laser welding of complete motor casing assemblies with the attachment of lugs to the outer circumference. The second phase of the project was specifically development-based where welding of test pieces were subjected to non-destructive and burst testing. Successful results were obtained.
In phase three, which involves pre-production, all the tooling, laser welding programs and other aspects will be addressed and the new camera-based system to perform the welding will be applied.
“This is a very exciting project. We have proven that we can provide a reputable and reliable joining process and Denel is highly impressed with the results,” Van Rooyen says.