Plastics for CNC Machining | Million Bright CNC

When to Use Plastics

Machined plastics are ideal when you need low weight, electrical insulation, chemical resistance, or low friction. They are common for prototypes, jigs and fixtures, housings, and functional parts. Plastics often require different design rules than metals to reduce warping and improve stability.

Common Plastic Options

ABS

Polycarbonate (PC)

Nylon (PA)

POM (Delrin/Acetal)

PEEK

Typical Uses

Prototype housings and covers
Jigs, fixtures, and assembly aids
Wear components and low-friction parts
Electrical insulating components

Pros

Low weight and corrosion resistance
Good electrical insulation options
Fast machining for many plastics
Low-friction materials available (POM, some nylons)

Cons

Can warp if thin or poorly supported
Lower stiffness than metals (depends on plastic)
Some plastics absorb moisture (e.g. nylon)

Machining Tips

Avoid very thin walls without ribs or support features
Plan for stress relief and flatness on larger parts
Define cosmetic requirements; machining marks vary by material
For assemblies, define fits carefully because plastics can creep

Finish Considerations

Many machined plastics are used as-machined. For cosmetics, bead blast may be possible on some plastics depending on requirements.

Explore Finishes

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Engineering Plastics