South Africa’s Aeroswift project which is set to revolutionise metal 3-D printing also known as additive manufacturing has been showcased at the Africa Aerospace Defence (AAD) exhibition at Waterkloof Air Force Base in Pretoria.
The programme, which was launched in 2011, is a partnership between the Council for Scientific and Industrial Research (CSIR) and the Aerosud Innovation Centre, which is a subsidiary of the Aerospace Development Corporation (ADC) that owns the Advanced High-performance Reconnaissance Light Aircraft or AHRLAC.
In 2012, international aerospace company Airbus announced that it would also collaborate to test the application of the manufacturing process in the production of large and complex aerospace parts.
This saw the development of the world’s biggest commercial powder bed metal 3-D printer to produce geometrically complex, high-value, low-volume parts using titanium powder. This would work well for the medical or aerospace industry which produces relatively small numbers of items, rather than the automotive industry which produces high numbers of cars a month.
The project has been funded by the Department of Science and Technology as part of its national titanium beneficiation strategy, to enable the country to export finished or semi-finished products instead of just the raw materials. South Africa has fourth largest titanium reserves in the world.
ADC Aeroswift’s Programme Manager for Additive Engineering, Marius Vermeulen, outlined the process.
“It’s a fairly new technology. We produce metal parts from metal powder. We melt this powder in layers using a laser. We build on the part layer by layer. The machine we’ve got is designed to do a wide range of materials – titanium, stainless steel, aluminium, cobalt, chrome – we are currently focusing on titanium. Titanium is a very good aerospace material. We dedicated this machine to titanium. Some of the new machines we build, we’ll dedicate to other materials. Our commercialization strategy is to manufacture parts – not to sell machines.”
What makes this machine different to commercially-available 3-D printers is that it is much bigger. It can produce parts up to 2 metres long, 600 mm wide and 600 mm high. The biggest commercial machine can produce parts 800 mm long, 400 mm in width and 500 mm high. Vermeulen said it can also do larger batches and up to ten times faster – this has an impact on the cost the longer a part spends in a machine, the higher the cost.
Further advantages of 3-D printing include the manufacture of very complex parts that had previously to be made from two or three separate elements and then joined together. Through the process of welding or riveting, there is a structural weakness. However, when it is done as a single piece without joins it is stronger and lighter.
Another advantage is that the part is built up from the raw material as opposed to taking a block of raw material and milling it away to get a small part. The rest of the material is then considered waste and has to be disposed of. This makes the whole process resource efficient, cost effective and with much less environmental impact as it reduces the amount of energy and materials used in the process. Vermeulen says he reuses the powder, 20 or 30 times.
Airbus’ Arnaud Montalvo says the company’s contribution to the project has been through the supply of documentation on setting the standards that they need to meet for quality in the production and manufacturing process. He says they have also tasked them with producing certain pieces of aircraft or components which Airbus is then evaluating.
He further elaborated on the advantages to the aviation industry of additive layer manufacturing:
“It is one thing making something the size of a salt and pepper pot.. its another thing making a large item like a wing flap or an air brake for a commercial jet airliner which might be a metre-and-a-half in length, which has to withstand all sorts of pressure. There is a very defined specification from a safety and quality point of view to make sure that it meets all the metal fatigue as well as weight and robustness standards and specifications.”
Montalvo noted that this type of manufacturing gives a much more precise and much more controlled way of manufacturing existing parts of an aircraft. He indicated that some of their partners are already starting to use similar technologies on engine parts and Airbus wants to apply it to other sections of the aircraft.
He said they were currently evaluating the parts produced to test the limits of what we can do with this technology.
The project has produced three titanium aircraft parts – a pilot’s throttle lever, a condition lever grip for the South African-built AHRLAC light reconnaissance and counter-insurgency aircraft and a fuel tank pylon bracket for a commercial aircraft. Future components on the cards for the AHRLAC include landing gear – and for other companies these range from engine components to trophies.
Vermeulen says there is no specific timeframe for commercial applications but they hope to have their first industrial machine ready by the end of 2019. Because of the cost factor, he says he does not see this technology replacing all other manufacturing technology – rather as a tool to produce parts for applications that are difficult to solve.
