Introduction
to 3D Printing

3D printing technology (also called Rapid Prototyping) is an additive computer-controlled process that builds parts inside a machine, layer by layer, using a variety of materials and processes. It's cool that 3D printing can output physical prototypes directly from the computer. The invention time is similar with CNC, in the late 1980s

information reference: https://www.nexmaker.com/doc/3_3dprinter/1.3Dprintingbackground.html

3D printing vs traditional manufacture

Cost

Additive technology has the advantage in prototype test or Customized part;
Subtractive technology is typically more economical when make parts in the 100 pcs;
Formative manufacturing has advantage in mass production.

Geometry

Additive technology can have complex geometry(inner flow channel, cavity, thin wall, and rib );
Subtractive technology has require in geometry. For example, CNC can't process inner flow channel which bend by itself;
Formative manufacturing has more require in geometry. For example injection need draft angle in molding. In addition injection molding can't make complex inner flow channel.

Materials

- Additive technology has a required material for every machine. For example, FDM 3D printing normally use ABS and PLA. So it would influence the effect of part;
- Subtractive technology can process almost every solid, for example, metal, plastic ,wood, etc;
- Formative manufacture could process material mainly in plastic.
Quality: Normally ,subtractive technology is similar with formative technology, and they are better then additive technology

Basic 3D principle