What are the general steps involved in plastic processing?

Plastic processing is a massive collection of different workflows and manufacturing steps, typically differentiated by the primary production method being used: plastic injection molding, blow molding, extrusion, 3D printing, machining/milling, thermoforming), or vacuum forming.

Across all these methods, the general principles of plastic processing are about the same up to a certain point. In all cases, plastic is made by extracting and refining crude oil into hydrocarbon monomers, further processing monomer bases into blended polymers (aka polymerization and compounding steps), and then shaping these polymers into plastic feedstock materials such as pellets or filaments. After this step, the different material formats will route to their respective production processes, like pellets to injection molding or shapes to machining.