A 4th axis is a rotary axis added to a CNC milling machine. While a standard 3-axis machine moves along the X, Y and Z axes, the 4th axis allows the workpiece to rotate during machining.
This is useful when a part needs machining on several sides or requires holes and features at different angles. Instead of removing and repositioning the workpiece manually, the rotary axis can turn it to the required position.
For example, 4th-axis machining is commonly used for flanges, shafts, cylindrical parts and components with holes distributed around the circumference.
There are also different ways to use a 4th axis. For simple indexing work, the rotary table moves to a specific angle and stops before machining. For more complex parts, simultaneous 4-axis machining allows the rotary axis to move together with the X, Y and Z axes.
The right 4th-axis configuration depends on the workpiece size, machining requirements and production process. Factors such as table size, load capacity, rotary speed and whether simultaneous machining is required should be considered before selecting the rotary axis.
Post time: Sep-24-2026