1. Double turn back method, with two rotation coordinates directly controlling the direction of the tool axis;

2. The downward rotation method has two coordinate axes at the top of the tool, but the rotation axis is not perpendicular to the linear axis;

3. Dual turntable mode, two rotation coordinates directly control spatial rotation;

4. Suspended workbench, with two axes on the workbench, but the rotation axis is not perpendicular to the axis;

5. One swing and one rotation, two rotational coordinates, one on the tool and one on the workpiece.