What is CNC machining?

CNC machining is a manufacturing process where computer-controlled machines remove material from a solid block to create a precise part.

CNC stands for Computer Numerical Control.

Think of it like this:

CAD design → CNC program → machine cuts material → finished part

For example, you might start with a block of aluminum. A CNC machine uses cutting tools to remove material until the block becomes the exact shape defined in the CAD file.

The main types

• CNC milling — cuts material using rotating tools; ideal for housings, brackets, plates, complex 3D parts.
• CNC turning — rotates the material while a cutting tool shapes it; ideal for shafts, pins, bushings, and cylindrical parts.
• 5-axis CNC machining — moves the tool/workpiece across multiple axes, allowing complex geometries and reducing setups.
• CNC drilling — creates precise holes and hole patterns.

What materials can be machined?

Common choices include:

Metals: aluminum, stainless steel, steel, brass, copper, titanium

Plastics: ABS, nylon, POM/Delrin, PEEK, PTFE, PC, acrylic

Why do engineers use CNC machining?

Because it can provide:

• High dimensional accuracy
• Repeatable parts
• Excellent surface finishes
• Fast prototypes
• Production-quality components
• No expensive injection mold required

For prototype manufacturing, CNC is particularly useful because you can upload a CAD file and get a physical metal or plastic part without committing to tooling.

In simple terms:

3D printing adds material. CNC machining removes material.

And for many functional prototypes, CNC machining is attractive because the prototype can be made from the same or similar engineering material used in the final product.