Additive manufacturing: the future is here
At Safran, 3D printing is very much part of the here and now. It has been used in the development of several Snecma engine parts, especially the Silvercrest which will power Dassault's Falcon 5X, and components of the Vinci Space engine. 3D printing is used to manufacture a part from a 3D model made using computer-aided design (CAD). The raw material, usually a metal powder, is applied to a work surface in thicknesses between 20 and 100 microns. The powder is applied in very precise layers by a laser, and thus the part is formed. Unlike conventional methods (forging and machining) which are based on material removal, 3D printing builds up components layer by layer. Hence ‘additive manufacturing' – the scientific name given to this process.
Reduced development cycles
While the technique has already been around for a few years, only very recently has it become efficient enough to produce metal parts boasting mechanical properties that are close – if not similar – to those obtained by forging. As a world leader in aerospace propulsion, Safran is currently leading the field in using 3D printing technology to manufacture its engines: "We're at the cutting edge of this field," emphasizes Pierre Letord, Head of the Industrial Means Division, Snecma (Safran). "We've already manufactured over 500 experimental parts using 3D printing, destined for the Silvercrest engine in particular. If the shape of a part needs to be changed, all we have to do is modify the CAD model," Letord adds. "We no longer need to change the machining process for machined parts or rework the molds for cast parts. Development cycles are considerably shorter with 3D printing."
A time for experimentation
Following the example of Snecma, Herakles (Safran), a company specialized in solid propulsion for space launchers, recently acquired a 3D printer, dispelling any doubts as to the benefits of additive manufacturing. "We began with a thermoplastic machine so that we could get to grips with the process and imagine different applications," states David Rodriguez, Head of the CAD/CAM Department. "The first results are encouraging: we are able to produce parts very quickly, and use them to see how the components fit together. We can also check that the mechanism simulations are working as planned during the CAD phases. We now want to shift up a gear and get a machine that works with metal," explains Rodriguez.
Towards complex parts on demand
In addition to quick production times, additive manufacturing can be used to make complex part geometries as a single piece or integrate additional functions that are impossible to obtain with machining, such as slots for sensors or assembled components. Lastly, the technology is well suited to making engine spare parts as and when they are needed, without needing to keep foundry casts in service. The future looks bright for additive manufacturing at Safran.