3-Axis vs 4-Axis CNC Milling: What Is the Difference?

CNC milling machines are described by how many axes they can move. Here is what that means for your part.

3-axis milling

The cutter moves in X, Y and Z. It reaches one side of the part in each setup. To machine other sides, the part is turned over and held again.

4-axis milling

A fourth axis rotates the part, so the machine can reach several sides in one setup. It also allows features around a cylinder.

Why it matters

Every new setup is a chance for small alignment errors and adds time and cost. With more sides machined in one setup, accuracy can improve and cost can drop on suitable parts.

What about turning?

Round parts such as shafts, bushes and pins are made on a CNC lathe by turning. A vertical machining centre (VMC) is a milling machine with a vertical spindle.

Which do you need?

Send us your drawing. We will tell you how we would machine it.

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