: First of all, this is not a personal attack as you are translating it. No, I am just trying to articulate a point here. Let's see some facts about your so- called advanced tech: Here is my strong points on the disadvantages of using 3D printing machines as compared to their master advanced fellows in large applications. It is summed up by one word, which you have probably never heard of. INCONSISTENCY.
There is inconsistency of materials produced by the 3D printers. Selective Laser Melting (SLM) which the commonly used method for 3D metal printers, produces varied materials basing on the structure being built. You will realize that a thick wall cools faster than a thin wall section there affecting the microstructure and the mechanical properties of the material.
There is an ongoing research on these impacts but for now the whole process still remains a myth to many (including you, I suppose).
Never let any mechanical device know that you are in a hurry.