It mainly includes the following five methods: one is the double turn head method,

Two rotational coordinates directly control the direction of the tool axis; The second method is a drooping rotating head, where the two coordinate axes are at the top of the cutter, but the rotation axis is not perpendicular to the linear axis; The third one is the dual turntable method, where two rotation coordinates directly control spatial rotation; The fourth one is a hanging worktable, with two axes on the worktable, but the rotation axis is not perpendicular to that axis; The fifth one is a swing starting from a rotation, with two rotation coordinates on one tool and one on the workpiece.