Around the world, additive layer manufacturing, also known more simply as additive manufacturing and popularly called three-dimensional (3D) printing, is a technology that is rapidly growing in usefulness and capability, and South Africa is no exception. Although lots of research and development (R&D) continues to be done (and needs to be done), the technology is today being used for commercial manufacturing purposes, albeit still only in certain niches. Again, South Africa is actively involved in both these aspects of the technology.
“In terms of what is happening in South Africa in R&D, of course the CSIR (Council for Scientific and Industrial Research) is the main player. They are doing a lot of work,” reports Aerosud ITC additive manufacturing programme manager Marius Vermeulen, who was chairperson of the recent Rapid Product Development Association of South Africa (Rapdasa) 2015 conference.
“Another big R&D player is the Central University of Technology (CUT), at the Centre for Rapid Prototyping and Manufacturing (CRPM). They do a wide range of work, in plastics and metals. They are starting to focus very heavily on the medical industry. Another significant player is the Vaal University of Technology, in Vanderbijlpark. They do a wide variety of things but they do have a focus on the tooling and casting sectors. They’re also looking at shoe manufacturing.” Other institutions that have become active in the field include the University of Stellenbosch and the North-West University on its Potchefstroom campus. “A lot of universities have some activities in this sector.”
Regarding industry, it is more difficult to give an overview. There are a lot of small companies involved. Additive manufacturing allows one- person enterprises to produce specialised items or make real-world models of computer-aided designs (CAD). “Quite a lot is happening in jewellery,” he cites. “Some things are happening in tooling. And, in many cases, industrial companies are using 3D printing for rapid prototyping before starting production using conventional methods. This technology opens up a wide range of new application areas. Worldwide, new companies are popping up, doing things which couldn’t be done before.”
In South Africa, the Department of Science and Technology has commissioned a roadmap for additive manufacturing in this country. This has involved a survey of the capabilities already existing in South Africa and of the active partici- pants in the sector. The aim is to identify niches the country can exploit and make a difference, and which should benefit from investment. The roadmap has reached the draft form level and this draft is expected to be released in the next two to three months. However, it is already clear that the production of qualified parts for the aerospace and medical industries should be focus areas, as should be the use of 3D printing to support the traditional manufacturing sector, particularly with regard to tooling and refurbishment.
“One of the main drawbacks of 3D printing is that it takes a long time to make each part,” he cautions. “On the other hand, it has very short lead times and allows great freedom of design. It’s great for high-value, low-volume production. Also, we’re already seeing a shortening of the production time for 3D printed parts and more and more powerful lasers, which are essential for the production of metal parts, are now available.”
The “Knowledge Gap”
Worldwide, the biggest single problem facing additive manufacturing is the lack of knowledge on the part of businesses seeking to use this technology. “The main problem is the knowledge gap in additive manufacturing in terms of designing the manufacturing process, finding the right business models to profitably use the technology and the validation of parts for critical industries,” highlights EOS area sales manager: Russia, Israel and South Africa Peter Rosker. “The additive manufacturing machine business is aware of these problems. We need to offer training to our customer companies and to people involved in additive manufacturing, to close this gap.”
(A German company, EOS was established in 1989, with a focus on additive manufacturing technology and machines from the start, and with an initial intent of enabling rapid prototyping. EOS now also offers additive manufacturing training and consultancy services.)
Outside the companies actually designing and manufacturing 3D printing machines, there are very few additive manufacturing professionals – unlike, for example, the case with computer numerically controlled (CNC) machines, for which there are now many professionals. “People need to be trained in additive manufacturing in how to use it,” he stresses. “Worldwide, lectures are now starting at universities. In South Africa, you are doing a great job. Universities here already teach this topic. They will produce lots of people who will be able to work in the additive manufacturing sector.”
Closing the knowledge gap will then open the way to meeting the next big challenge in the sector. “In future, additive manufacturing machines will have to be redesigned to be integrated into high-volume production environments.”
Rosker expects that additive manufacturing will transform the world. But it will make its first big impacts in the aerospace and medical sectors. “Aerospace will be the big driver in the coming years.” Already, US major aero engine manufacturer General Electric is ramping up 3D printer production of fuel nozzles for its latest-generation LEAP engine to 40 000 a year. “We expect them to expand [additive manufacturing] to other parts in due course,” he says.
In the Lead
South Africa’s Aeroswift project, a joint development by private-sector company Aerosud ITC and the Council for Scientific and Industrial Research’s (CSIR’s) National Laser Centre (NLC), has resulted in the development of the world’s biggest powder bed additive manufacturing machine. This is the Aeroswift machine, which is currently in its commissioning process in Pretoria. The project has largely been funded by the Department of Science and Technology. (Aerosud ITC is now a completely separate company from major South African aerostructures manufacturer Aerosud Aviation.)
“To our knowledge this is the biggest and fastest powder bed fusion system there is,” says Vermeulen. “The machine can make parts as big as 2 m × 0.6 m × 0.6 m, using a 5 kW laser system. The assembly of the system took about two years. We hope to complete the commissioning within the next six months.”
Aeroswift will produce metal, particularly titanium, parts. “It’s typical powder bed additive manufacturing,” he explains. “You start with a CAD part. Still on the computer, you slice that into very thin layers. These provide the patterns or images that the machine will follow as it builds up the part. In the machine we have metal powder and we can put down a very thin layer of this powder. We then use the laser and a scanning system and we melt the CAD image into the layer of metal powder. Then we lower the bed of the machine, add a new layer of metal powder and repeat the process. The end result is a container full of metal powder as well as the part. You remove the part and reuse the metal powder.”
Powder bed fusion is one of two metal 3D printing technologies. The other approach is directed energy deposition. In this, the material is deposited from the side as it is melted (whether by laser, electron beam, arc or some other method). The advantage of this system is that it allows the production of large parts. Its disadvantage is that it cannot produce complex parts.
Until now, powder bed fusion technology has allowed the production of complex parts, but not large parts. Aeroswift will significantly increase the size of parts that can be made with powder bed additive manufacturing. “In this programme, [Aerosud ITC ] was more responsible for the mechanical systems, and the CSIR NLC for the optical systems.” The machine is housed in a specially modified building on the CSIR’s main campus.
The Aeroswift machine is a R&D platform and so it is overengineered and overspecified, compared with a straight-forward production machine. All being well, it will, however, be used to manufacture metal parts for production programmes, especially for the Aerosud ITC/Paramount Group joint Ahrlac light surveillance and attack aircraft programme. The current focus is on making flight-ready demonstration parts by the end of 2017.
Additive layer manufacturing is already playing an important role in the Ahrlac project. “3D printing has transformed the Ahrlac programme,” reports Ahrlac programme manager Paul Potgieter Jnr. “Three-D printing suits aviation manufacturing very well. In general, aviation manufacturing is not very high volume, but the parts are very complex. In 3D printing, complex parts can be made in one go, instead of being composed of many smaller parts put together. It will transform aviation manufacturing.”
Thanks to 3D printing, there is now no longer any need for Ahrlac to make tools before being able to produce a new part. A complex part can be ‘printed’ overnight and tested the next day. If it is not a success, the engineers can just change the design and print the new part without having to develop a new tool first.
At the moment, the company is printing second- and third-degree parts of the aircraft in plastic – parts, which, if they fail, cannot cause the aircraft to crash. These include air inlets, air valves and throttle grips and they are being flown on the aircraft. “We hope to add metal 3D-printed parts next year,” he says. These will be titanium parts and will form part of the engine cradle. “The ultimate plan is to print the engine cradle as one part.”
“We’re also printing – using carbon – special tools for the Ahrlac. Aircraft use lots of special tools,” he added. “Tools which once took weeks to produce can now be done overnight.”
In terms of quality, a lot of effort has gone into ensuring that the printed titanium parts will be of the same quality as machined titanium parts. Regarding the plastic parts, only aviation-certified materials are used. “We’re happy with the quality of the parts,” he assures.
“I think our biggest journey has been to get our engineers to think, to imagine, what is now possible, and [to] no longer think on conventional lines,” states Potgieter. “It took time to work out how to properly use this technology, but we have achieved this and we are now producing functional parts with long lives. In the end, I think we’ll be able to print the entire fuselage of the Ahrlac!”
The use of additive manufacturing has also helped revolutionise product development at South African defence company Airbus DS Optronics. It is one of the technologies adopted by the company to enable it to carry out rapid prototyping of new products. The company is renowned for its electro-optical sensor payloads, fitted to fixed-wing aircraft, helicopters and unmanned air vehicles. “Since 2011, when we started with additive manufacturing, we’ve produced four new payloads,” says company principal mechanical engineer Gerhard Smit. “Before that, between 2002 and 2010, we produced three.” (Airbus DS Optronics is 70%-owned by Airbus Defence & Space, part of Europe’s Airbus Group, and 30%-owned by South African State-owned defence industrial group Denel.)
“On a payload, rapid prototyping has reduced the development time from three years to nine months,” he highlights. This includes the use of a five-axis Haas milling machine, computer modelling, simulation and streamlined administration as well as additive manufacturing. “Of that [27 month] reduction, about nine to 12 months are due to additive manufacturing alone.”
Smit points out that electro-optical systems had previously taken years to develop because of their complexity and the interdependence between all the components that made up the system. These could include visible-wavelength, infrared and thermal imaging devices, laser pointers and laser rangefinders. In addition, the payload had to be stabilised to eliminate the vibration from the carrying aircraft (an especially severe problem with helicopters).
These systems are developed primarily for defence and police missions and must go through the complex development process typical for defence systems. This, he notes, starts with the requirement review, followed by the concept design review, then by the detailed design review, the construction and qualification of the prototype system, the development of the production standard system and the start of production, and the development and implementation of the support programme for the operational system. Rapid prototyping has greatly accelerated this process.
The company has its own in-house additive manufacturing capability. However, when there is a large amount of work to be done, it also contracts out. The manufacture of 3D-printed production parts is also contracted out, as the company does not yet have the type of machine required for this. “We typically produce between 4 kg and 5 kg of rapid prototyping material a month,” he reported. “The material comes in cartridges of 1.5 kg, each costing R15 000. It’s expensive but it is worth it!”
Regarding additive manufacturing in the medical sector, the leader in South Africa is the CRPM at CUT, in Bloemfontein. The centre has ten additive manufacturing machines, making it one of the biggest units of its kind in the southern hemisphere.
“We have successfully developed medical implants and devices in titanium, which had not been done in South Africa before,” points out CRPM head Gerrie Booysen. “We have also used 3D printing to develop preplanning models, jigs and drilling guides for the surgeons.” These serve to help the surgeons to plan surgery to, in particular, remove tumours and cancerous tissues. These models, jigs and drilling guides are complex structures, but they must be designed and produced rapidly because of the rapidity with which aggressive cancers spread. The centre also produces prostheses to hide the gaping holes that can be left in the faces of the patients by radical surgery. The great advantage of additive manufacturing is that its allows the design and manufacture of individual patient-specific prostheses.
For the CRPM, involvement in medical matters has involved a steep learning curve. The surgeons, likewise, have been through a similar learning curve with regard to 3D printing. But it has established the CRPM’s reputation internationally. “When some of these cases were presented at world conferences, we realised that the work done here is of the highest standard,” he reports. “The interest generated at these events has been very inspiring and we have been asked to collaborate with countries such as India, Colombia, Mexico and the US, to name but a few.”
The CRPM is in the process of getting ISO 13485 accreditation (for the manufacture of medical devices). “This will enable us to be globally competitive and manufacture standard medical devices as well as patient-specific implants in titanium,” he explains. “The nature of additive manufacturing allows us to work with doctors or companies anywhere in the world and, once we have International Organisation for Standardisation accreditation, we will be able to produce prostheses at a very competitive price, owing to the weakening rand.”
At home, CUT and the CRPM hope to obtain funding to create a maxillofacial prosthodontics unit, which would use 3D printing to help people who suffer unsightly facial disfigurements from cancer surgery. The aim is to help patients in State hospitals, which have no money to provide such prostheses. More generally, the centre wants to advance and strengthen the use of additive manufacturing in the medical sector in South Africa and, in particular, the Free State. “We are currently working with a number of role-players to develop a new design of a titanium mechanical heart valve which will be manufactured using additive manufacturing,” he says. This would be cheaper than imported units. The target markets are the South African State health sector and African medical markets, which cannot afford to import such devices from Europe or the US.
The growth of the additive manufacturing sector is reflected in the parallel growth of the size of Rapdasa. While the 2014 conference had 130 delegates, the 2015 conference (which was the sixteenth edition) saw 230 people attend. Likewise, the participation in the conference by industry has also grown greatly.
“It’s a new technology, so, with a new technology, you start off with a lot of focus on R&D,” concludes Vermeulen. “But, as it matures, you expect a greater focus on industry. That is what is happening in South Africa. We’re seeing ever greater use of the technology by industry.”