Engineering Resource

How the two differ

On a 3-axis machine the part is fixed and the tool moves in X, Y and Z. Each new face normally means a new set-up. On a 5-axis machine two rotary axes move as well, so the tool can approach the part from almost any direction and several faces can be machined in one set-up.

Where 5-axis wins

• Complex, contoured surfaces and freeform geometry.
• Undercuts, deep pockets and features that are awkward to reach from one direction.
• Parts with many angled faces or holes, where fewer set-ups means less stack-up error.
• Parts that must be finished in one set-up to keep features in relation to each other.

Where 3-axis is the right answer

Prismatic parts, plates, simple hole patterns and parts that are naturally accessible from a few orthogonal directions are usually faster and cheaper on a 3-axis machine. Forcing them onto a 5-axis machine buys nothing but a higher hourly rate.

Tolerance and consistency

We hold ±0.005 mm on 3-axis work and ±0.01 mm as standard on simultaneous 5-axis. The figure that matters more than the headline number is stack-up: every re-fixturing adds error, so a 5-axis single-set-up process can produce a more consistent part even when its per-feature tolerance is nominally wider.

The cost logic

Five-axis machine time costs more per hour, but it can still be cheaper overall if it removes two set-ups, a fixture and a re-fixturing error. Judge the choice on the total process, not the hourly rate — and on batch size, because the set-up saving repeats on every part.