The Council for Scientific and Industrial Research’s (CSIR’s) National Laser Centre (NLC) has introduced several new additive-manufacturing laser technologies, including the Laser Engineered Net Shaping (LENS) technology.
CSIR Laser Materials Processing competence area manager Dr Federico Sciammarella tells Engineering News that this technology is the first of its kind in South Africa.
LENS technology uses a high-power 500 W to 4 kW laser to fuse powdered materials into fully dense three-dimensional (3D) structures, he explains.
“The LENS 3D printer uses the geometric information contained in a computer- aided design solid model to automatically drive the process, as it builds a component layer by layer.”
He adds that additional software and closed-loop process controls ensure the geometric and mechanical integrity of the completed part.
The process is housed in a hermetically sealed chamber, which is purged with argon so that the oxygen and moisture levels stay below ten parts per million. “This keeps the part clean, preventing oxidation,” he says.
To create high-quality 3D parts with integrity, the metal powder feedstock is delivered to the material deposition head by a powder-feed system, which is able to precisely regulate mass flow, Sciammarella explains.
The system can also be used for the refurbishment or repair of old parts, he adds. Newer materials can be used on old parts, making them last longer.
The CSIR is also collaborating with aeronautics company Aerosud on a project called Aeroswift, which is funded by the Department of Science and Technology (DST).
The Aeroswift project comprises the development of a high-speed large-area additive-manufacturing technology platform. The DST invested R28-million in this venture.
A specialised 5 kW IPG single- fibre diode laser was recently acquired with a portion of these funds.
“This system will be the first of its kind in the world, as it will be able to build aero- space components with an envelope of 2 m × 500 mm,” says Sciammarella.
He notes that this is critical, as large structures, for example, aircraft wing components, are difficult to build in a small area, as parts would have to be built separately and then joined at a later stage. A technology that can cover a large area fast, efficiently and with precision is required to reduce fabrication time and improve the buy to fly ratio.
In these areas, the NLC’s expertise in lasers and processing and Aerosud’s expertise in building systems complement each other. “Combining this knowledge is what makes Aeroswift possible,” he says.
Sciammarella emphasises that the laser will only be stationed at the CSIR NLC for a limited time as it is only one component of the Aeroswift system.
“We are developing and building the support structures for the entire Aeroswift system, or what we call high-speed large-area selective laser melting, at the NLC,” he states.
After the system has been developed, it will then move to the Centurion Aerospace Village, where it will be used as the pilot plant for building larger components, he says.
Sciammarella says the laser is the key component in the Aeroswift system, as it is bought and the system then built around it.
The NLC is also working on another additive-manufacturing initiative, Umuvi, which is Sotho for wasp. The name was chosen as wasps build their nests using additive manufacturing processes.
“Umuvi will be the next-gene- ration additive-manufacturing system. It will be far quicker and more efficient. This will result in ultrahigh-speed additive manufacturing,” states Sciammarella.
The Umuvi initiative is being funded by the CSIR, working through the NLC. “We are not focusing only on the first technology, being Aeroswift, but also thinking about how the technology can be improved,” he states.