3D printing is great for prototyping, and for small production runs, but economies of scale are not in favor of 3D printing for mass production. The material de

3D printing is great for prototyping, and for small production runs, but economies of scale are not in favor of 3D printing for mass production. The material deposition rate is too slow, and the machine cost is too high, compared to traditional manufacturing methods. I have one part that I designed several years ago which is part of the APU installation on a certified aircraft. The part we flew during flight test was 3D printed aluminum (AlSi10Mg). The turnaround time from completing the design, to having a completed, inspected part ready to be installed, was about a week. For a machined part, the turnaround would have been about 6 weeks, and about 6 months for a cast part. But then when we looked at manufacturing methods for the production part. 3D printing directly in metal was the most economical method for up to 10 parts, because there is no up-front tooling cost, but the recurring cost of both the raw material and the machine time is very high. For 10 to a hundred or so parts, the most economical method was investment casting using a 3D printed wax preform, and for more than 100 or so parts, the most economical method was to buy traditional permanent closed-die tooling for the casting.