What's the difference between a 3D printer and a CNC machine tool?

CNC machine tools are pre-programmed to process mechanical parts by cutting. The working principle of 3D printer is similar to that of CNC machine tools, and it also works according to computer instructions. The difference is that it makes products by stacking raw materials layer by layer. Therefore, 3D printing is also called additive manufacturing. The premise of the normal operation of the 3D printer is to input a designed electronic blueprint or design document, which is responsible for telling the 3D printer where to put the raw materials. Then, under the guidance of the design document, the 3D printer first ejects solid powder or molten liquid material to solidify it into a special plane thin layer. After printing, the printed model needs post-processing, such as curing, peeling, model trimming, etc. Finally, make the required model.