• Puneet Bhalla

3D Printing or Additive Manufacturing (AM) was first tested in 1983 by inventor Chuck Hull. Conventional “subtractive manufacturing” involves carving out items from a single block of material, whereas AM involves adding plastic or metal layer by layer according to a computer generated design to manufacture a product. Over the years a number of processes that differ in the method of depositing of layers and their binding have been developed. The technology in the earlier years did not evolve enough for it to find mainstream support and its use was restricted to production of computer generated models and prototype research. Advances in metallurgy, miniaturisation and processing have now made it a more viable competitor to conventional manufacturing. It is even being called the third industrial revolution.

Commercial enterprises having recognised the transformative potential of 3D printing, both in designing and manufacturing, are increasingly investing in it. It allows faster design iterations, providing flexibility for refinements and variations and produces more accurate 3D scaled models for testing. This helps in accelerating product development and manufacturing with corresponding cost benefits. It helps overcome constraints of conventional manufacturing and allows for more precision in manufacturing to produce more complex parts. The process allows for more cohesive structures and components can be constructed using much fewer parts, making them lighter, sturdier and more efficient. Large factories with their assembly lines can also be done away with. Existing parts can now be redesigned and designers can be more audacious in their pursuits, stepping beyond the constraints of conventional design and manufacturing, while seeking innovative solutions or entirely new capabilities. The manufacturing process requires less material, reduces wastage during production and is more energy efficient, making it potentially more environment friendly. Objects can be created on demand, thereby eliminating costs, logistical complexities and wastages related to surplus inventories. Initial printers were capable of handling single materials only but the multi-jet technology is allowing combining of materials to produce varied material properties – mechanical, thermal and chemical. Nanotechnology coupled with 3D printing promises exciting opportunities in the future. Already, availability of cheaper printers has made the power of designing and producing publicly available. This democratising of manufacturing has the potential to revolutionise innovation. Market researcher Gartner forecasts that worldwide spending on 3D printing will rise from $1.6 billion in 2015 to around $13.4 billion in 2018.[1] Despite the excitement, there are experts who say that the technology might only evolve to supplement the conventional mass manufacturing methods that will continue to be faster and cheaper. They instead favour its suitability for niche and customised production.

Space exploration has always been costly due to its requirement of low volume, customised and at times unique components. 3D printing is being seen by the space industry as enabling to the development of future space infrastructure. Various R&D efforts both for ground based as also in orbit manufacturing are being supported with an aim to develop parts that could meet the stringent high performance and high reliability criteria required for space operations. NASA along with US rocket engine maker Aerojet Rocketdyne has successfully tested a rocket engine injector and an advanced rocket engine thrust chamber assembly using copper alloy materials, in different configurations.[2] The components proved themselves in tests where they were subjected to pressures of up to 1,400 pounds per square inch and temperatures up to 6,000 degrees Fahrenheit to produce 20,000 pounds of thrust.[3] NASA has claimed that 3D technology enabled designers to create more complex injectors while at the same time reducing the number of parts from 115 to just two.[4] This resulted in more efficient processes and also provided better thermal resilience. While the traditionally constructed injectors cost about $10,000 each and took six months to build, the 3D printed versions cost less than $5,000 and reached the test stand in a matter of weeks.[5] These tests have provided confidence in the technology and paved the way for its use in replacing other complex engine components.

Already, many small 3D produced parts are flying in space onboard US and European satellites and more are being developed. ESA and European Commission’s Additive Manufacturing Aiming Towards Zero Waste & Efficient Production of High-Tech Metal Products (AMAZE) project, has 28 European companies as partners that are looking at perfecting 3D printing of high quality metal components for aerospace applications. NASA is also evaluating using the technology for manufacturing composite CubeSats. China has also started investing in this technology and on its last manned space mission in 2013, their taikonauts occupied customised 3D printed seats. In December 2014, Chinese scientists have claimed to have produced a 3D printing machine, which could be used during space missions. Private companies the world over are investing heavily in the technology for aerospace applications.Japanese Space Agency JAXA along with Mitsubishi is working at producing 3D components for a new large-scale rocket that the two are expected to develop by 2020. Swiss company RUAG Space has built an antenna support for an Earth observation (EO) satellite that will replace a conventionally manufactured one after tests. The engine chamber of SuperDraco thruster to be used on the crew version of SpaceX’s Dragon spacecraft, capable of producing 16,000 pounds of thrust, is manufactured using 3D printing. A team of engineering students from the University of Arizona, with help from 3D printing company Solid Concepts, recently assembled a 3D printed rocket within a day and successfully tested it. Planetary Resources, a private company seeking space exploration and asteroid mining has collaborated with a company, 3D Systems for developing and manufacturing components for its ARKYD Series of spacecraft using its advanced 3D printing and digital manufacturing solutions.All these efforts are providing solutions that are cheaper, have lesser parts and have comparatively shorter developmental timelines.

In the future, the technology could be used for entire structure fabrication that would involve integrating many of the system’s geometries into structural elements during production. This would reduce the number of parts, eliminate most joints or welds, simplify the design and production, reduce the number of interfaces and make the system more efficient and safer. Such vehicles would better sustain the rigours of launch and space exploration. Integrated structures would even enable reconceptualising space architectures, impacting on their design, sizes and functionality.

The most exciting opportunity is 3D printing of objects in space – an idea that has the potential to cause a paradigm change in the way we look at space exploration. The concept has been debated for decades and NASA has also conducted some experiments since theSkylab space stationof the 1970s. In 2010, it collaborated with a US company Made in Space to develop and test a 3D printer that could operate in microgravity aboard the International Space Station. The microwave oven sized printer, previously tested on suborbital flights, was installed on board the station on 17 November. After two calibration tests, on 24 November 2014, on command from the ground controllers, the printer produced the first 3D object in microgravity. The object was a faceplate of the printer itself, demonstrating that the printer could make replacement parts for itself. Initial results have shown that layer bonding might be different in microgravity, but this would have to be substantiated by further testing on more such produced parts in the future. These parts will subsequently be returned to Earth where they will be compared with similar samples made by the same printer before launch and also analysed for effects of microgravity on them. This would help in evaluating the variance and possible advantages of additive manufacturing in space and in defining the roadmap for future developments. Meanwhile, Europe’s POP3D Portable On-Board Printer designed and built in Italy is also scheduled for installation aboard the ISS next year.

Producing parts and structures in space potentially provides a host of benefits. Structures being constructed on Earth have to be built in an environment that is different from where they would operate. These parts also have to survive the vibrations and high ‘g’ stresses of launch. Freed from these constraints, novel space architectures, more optimised to the microgravity environment, can be imagined and developed. 3D printers in space would enable astronauts manufacture their own components and tools, undertake repairs, replace broken items and respond to evolving requirements without being dependent on support from Earth. This would bring down logistical requirements related to deployment of structures in space, while improving mission efficiency and reliability. NASA is even funding research into the possibility of making food in space using a 3D printer. This would overcome the current issues related to food shelf life, variety and nutritional requirements. It would be possible to have human missions of longer duration and venturing much further into space. Made In Space has an ongoing project R3DO that seeks to recycle 3D produced broken or redundant parts to create new ones, thereby helping reduce space waste. The technology in the future could be used for space based construction of large structures – even entire spacecraft in space.

Another concept being envisaged is the use of 3D printing for construction of large housing structures, roads and launch pads using the resources available in-situ on celestial bodies. Concrete houses being produced through 3D printing have already been demonstrated. Both NASA and ESA are exploring printing of objects using Regolith, the powdery substance that covers much of the surface of the moon. Besides the huge savings in cost and time, such habitats would be more suited to the local hazardous environment. The printers could either be controlled from Earth or make use of automation technology on robots or artificial intelligence. These capabilities would be a great step forward for human interplanetary exploration.

3D printing is making rapid strides and its applications are being recognised by industry. Scientists are working to smoothen out the inefficiencies and shortcomings of the processes as also evaluating potential opportunities. Developments in the space domain are promising but these would have to be put through rigorous testing before being cleared for regular use. Qualification and verification standards that would eventually be defined for this new industry would have to be more stringent for use in space. More complex printers will have to be devised for construction of larger parts. Currently, most construction is focussed on building frames and structures but in the future would also require manufacturing techniques to producing working electronic components.[6] For production in space, bigger printers would bring forth issues of mass, volume and power requirements, each one of which is critical for space launch and operations. Some methods would also have to be devised to bring together the parts so produced. The new technology provides an avenue for space industries the world over to graduate to common standards of software as well as hardware. This would allow a larger pool of scientists and engineers coming together learning and benefiting from each other. At the same time, and the policy makers would also have to come up with requisite regulatory framework.

In India, 3D printing technology is still in its infancy and its penetration is low among industry is low. Most institutions continue to use it for producing 3D Computer Assisted Design (CAD) models and for prototype testing. Some global additive manufacturing companies have gained foothold in India through collaborations and there are some indigenous initiatives too. Isolated research is being undertaken by some private and public sector entities including the DRDO. Private companies are collaborating with some engineering institutions like IITs to promote research. There is also the Additive Manufacturing Society of India (AMSI) that seeks to promote 3D printing & Additive Manufacturing technologies. Applications for Defence and Aerospace are two important sectors that most companies are focussing on. ISRO chairman, after the successful Mars Orbiter Mission, mentioned 3D Printing as one of the technologies that he wishes to see Indian engineers build upon in the future. India has lagged behind in conventional manufacturing and metallurgy. It could leverage its advances in software technology and collaborate with international experts to initiate activities in this sunshine sector. While increased awareness and commercial benefits will drive industry to invest in the sector, space initiatives would require the government to play the vital supporting role while seeking participation from industry and academia. Investments would be required in planning and executing the supporting infrastructure required to enable fabrication processes, in creating knowledge and capabilities through education and training and for provision of adequate R&D facilities.

[1] “From earphones to jet engines, 3D printing takes off”, 09 November, 2014

[2] “3-D Printed Engine Parts Withstand Hot Fire Tests”, 14 November, 2014

[3] TheAerojet Rocketdyne RS-25engine powered NASA’sSpace Shuttleand will power the upcoming Space Launch System (SLS), a heavy-lift, exploration-class rocket currently under development to take humans beyond Earth orbit and Mars.

[4] ww.space.com/22568-3d-printed-rocket-engine-test-video.html

[5] http://www.space.com/22119-3d-printed-rocket-part-test.html

[6] http://www.space.com/26676-3d-printing-international-space-station.html