When you think of additive manufacturing, also known as 3D printing, you may think of intricately latticed parts for consumer products, furniture, or medical devices. But a rocket engine?
The Terran 1 rocket, which launched last March, was 85% 3D-printed, including its fuselage and nine engines. Much of the rocket was made with unique metal 3D printers from Relativity, a startup that prints rockets with 100x fewer parts in 60 days or less, crushing the industry standard of 18 months.
Terran 1 is just one example of how the aerospace industry remains at the forefront of additive manufacturing and why organizations like NASA and the European Space Agency (ESA) are funding projects to realize even more gains from this technology.
In this blog, we’ll examine the long list of benefits 3D printing offers for aerospace manufacturers.
Many of the systems and assemblies used in aerospace are made up of dozens or even hundreds of parts, each of which must be designed, tested, manufactured, and assembled. Not only is this time- and resource-intensive, it creates a potential vulnerability at every point where two parts are joined.
Part consolidation is the process of redesigning an assembly to merge as many parts as possible without compromising strength, functionality, or performance. This often results in designs with complex shapes and structures that are difficult or impossible to produce using conventional means but are ideal for additive manufacturing that builds parts layer by layer.
Advantages of part consolidation are numerous, including:
• Smaller, less complex supply chain
• Faster production and quicker time to market
• Lower risk of failure at weld points, rivets, bolts, etc.
• Better strength-to-weight ratio
One of the biggest impacts of additive manufacturing generally and part consolidation specifically is cost savings. Fewer parts mean fewer suppliers and much less time spent shipping parts and assembling them. Printing a single part locally also reduces the cost of quality control and inventory management. And it minimizes the risk of delays caused by supply chain disruptions.
In addition, when engineering teams need to do failure analysis, analyze wear and tear, make minor improvements, or redesign the part entirely, there is only one part to work with instead of dozens or a hundred. In these cases, the time and cost savings are substantial.
Because of the time and cost savings additive manufacturing creates, it affords aerospace engineering teams more flexibility when iterating on design improvements.
Normally, tight lead times constrain designers and engineers considerably. But with 3D printing, engineers can spend more time exploring and experimenting to find the ideal solution — without the normal concerns about going over budget or delaying the schedule.
Additive manufacturing also enables rapid prototyping, which further reduces the time and cost of every iteration.
Rapid prototyping with metals can be quite expensive. In these cases, simulation software speeds the process by reducing the number of iterations until the new component is perfect.
Simulation allows engineers to pre-deform a 3D model and proactively adapt to distortions likely to occur during 3D printing, creating a more accurate design more efficiently and with lower costs.
This impeller, for example, used advanced simulation to test a lightweighted design. The resulting impeller not only weighed less but was tested successfully in a full-scale engine, withstanding actual environmental conditions at a variety of loads.
The layer-based nature of additive manufacturing gives aerospace engineers access to design techniques that are simply not available for parts manufactured through traditional means.
One example is lightweighting, which is critical in aerospace. Every bit of material removed from a part reduces its weight, which in turn reduces fuel costs. At the same time, the part must still meet strict requirements for stability and rigidity, both of which generally add to its weight. Lightweighting uses topology optimization to find innovative structures that minimize weight while retaining strength. These structures are generally only possible to make with additive techniques.
This satellite antenna bracket, for example, was redesigned with lightweighting techniques. The resulting part weighed 40% less than the previous version and exceeded its rigidity requirements by more than 30%.
Similarly, this thruster mechanism for satellite positioning incorporated seven topologically optimized brackets that reduced the thruster’s weight and increased its efficiency while meeting expectations for pointing accuracy and overall functionality.
The design freedom of additive manufacturing extends to material selection as well. Again, weight reduction in aerospace has a huge impact on fuel efficiency. Additive techniques allow aerospace manufacturers to consider a wide range of new materials that weigh less than conventional materials but still provide adequate strength.
These materials, including ULTEM 9085 resin, are not appropriate for conventional manufacturing techniques. But with 3D printing, they can be used to make a wide range of cabin parts, such as air ducts and wall paneling, leading to substantial weight reductions.
Another example is GRCop-42 (Cu-4 at.% Cr-2 at.% Nb), a dispersion strengthened copper alloy with high strength and impressive thermal conductivity, developed by NASA, and used to build improved rocket thrusters.
Aerospace parts are frequently exposed to extreme temperatures as well as very wide swings in temperature. The retaining brackets on this telecommunications satellite, for example, needed to be very strong but are regularly exposed to temperatures ranging from -180°C to 150°C, which creates a great deal of stress on the material. Titanium provided the optimal combination of weight and thermal conductivity, but the resulting part did not meet performance expectations.
Additive manufacturing, however, gave the design team the freedom to consider other designs without changing the material. The new design incorporated part consolidation and lightweighting techniques, creating a precision-made bracket that weighed 300g less, reduced production costs by more than 20%, and easily met the temperature resistance requirements.
The aerospace industry continues to push ahead with innovations in additive manufacturing, driven by all of these benefits as well as dedicated funding from NASA and ESA. One area of special emphasis is software that helps engineering teams get maximum value from 3D printing systems.
For the redesigned impeller mentioned above, for example, it was Amphyon simulation technology, now integrated into 3DXpert, that helped prevent deformation while significantly reducing calculation time.