Much of the attention to 3D printing, or additive manufacture, these days is devoted to manufacturing new and much better metal parts. But the big move in aftermarkets may be extensive use of 3D-printed plastics to replace and improve cabin-interior parts.
Bryan Hodgson, aerospace applications leader at 3D Systems, explained how his firm is helping airlines, including Emirates Engineering, to exploit 3D plastics.
The first step is deciding what parts to print. Cost, complexity and other factors enter this calculation, but the big factor is volume: the smaller the count, the better 3D printing looks. Hodgson says, as a general rule of thumb, any part that is needed in a quantity of 15,000 or less is a good candidate for printing rather than producing by injection molding.
3D printing can then bring two basic sorts of advantages. The first is a rapid acceleration in the design cycle for improving replacement parts, and the second is in the total cost of ownership of the part, including production costs and the costs of operating an aircraft with the part.
With the traditional injection molding process, it can take four to 18 months to design a new part, get it certified and put it on an aircraft. Obviously, much of this time is taken up by designing and making the equipment to produce the prototype part, test and tweak the design and then make the part. Many firms thus do hundreds of digital designs before they invest in the expensive tooling. “The drawback is you have to wait a long time,” Hodgson said.
In a webinar sponsored by Michigan State University’s Department of Mechanical Engineering, Hodgson said 3D’s FR1200 printing machine and process enabled designs to be changed on the fly as parts are printed, so it takes less than a month to get a new part on an aircraft. Hodgson said once engineers are fully qualified on the 3D technique, that period can be further shortened, to two weeks.
One operating advantage of 3D-printed parts is that they can be made lighter than the parts that they replace, thus cutting fuel burn. The FR1200 uses a powder-based plastic that is 10% lighter than ULTEM, a thermoplastic commonly used for cabin-interior parts.
And 3D printing gives engineers a design freedom they do not have with injection molding. As a result they can design a part to serve its function with less total volume and material, thus saving another 20% or more in weight.
In short, better plastic parts can be made faster, lighter and cheaper with 3D printing. And that does not count the capital saved by printing, rather than molding, small quantities.