5 most popular plastic raw materials used for CNC machined prototype parts in the automotive industry:

Acrylonitrile Butadiene Styrene (ABS):
ABS is a common thermoplastic material widely used for CNC machined automotive prototypes.
It offers a good balance of mechanical properties, impact resistance, and dimensional stability, making it suitable for a variety of automotive applications.

Polycarbonate (PC):
Polycarbonate is a high-performance thermoplastic known for its optical clarity, impact resistance, and heat resistance.
It is frequently used for CNC machined prototypes of automotive lighting components, displays, and other transparent or semi-transparent parts.

Polyoxymethylene (POM), also known as Acetal or Delrin:
POM is a engineering plastic that provides excellent dimensional stability, low friction, and good mechanical strength.
It is commonly used for CNC machined prototypes of automotive gears, bushings, and other precision mechanical components.

Polyamide (PA), or Nylon:
Polyamide, particularly Nylon 6 and Nylon 66, are popular choices for CNC machined automotive prototypes due to their high strength, stiffness, and wear resistance.
These materials are often used for prototyping of automotive structural components, brackets, and functional parts.

Polyetheretherketone (PEEK):
PEEK is a high-performance thermoplastic with excellent thermal and chemical resistance, as well as good mechanical properties.
It is increasingly used for CNC machined prototypes of automotive components that require elevated temperature and harsh environment performance, such as engine and transmission parts.

These five plastic materials - ABS, Polycarbonate, POM, Polyamide, and PEEK - are widely utilized in the automotive industry for CNC machined prototype parts due to their unique combinations of mechanical, thermal, and chemical properties, which closely match the requirements of many automotive applications.