Little understanding, just say a simple chestnut, assuming I want to make a plastic part, the lowest level of method is to use plastic blocks constantly chipped, plastic blocks into the shape I want (and then say it is not suitable for production, even if it is a small-scale production is not good enough to make); a little more advanced is to dig holes in the metal block, drilling ... ... (in fact, is to make molds), and then injection molding (very suitable for production, but not suitable for small-scale production). ...(actually make molds), and then injection molding (very suitable for production, but not suitable for small-scale production.) The most advanced is probably 3D printing, to what kind of hit what kind of (in addition to 3D printer is more expensive in addition to acceptable, and open mold compared to 3D printer is just a drop in the bucket). Or put it this way: the present is sculpture, can only cut a knife to modeling, where the lack of something can only slowly think how to explain to the boss; 3D printer is ceramic molding, what modeling to have what modeling, where there is a lack of something to make up for what things there.
Please adopt, thank you!