Post-processing method for special seven-five axis linkage machine tool

A post-processing method for a special seven-five axis linkage machine tool, comprising the following specific steps:

• step 1:
• building a multi-body kinematic model according to the structure of the machine tool, and building the multi-body kinematic model according to the sequence of workpiece-turntable-machine tool-cross beam-ram-milling head-cutting tool;
• step 2:
• establishing position coordinate transformation matrices according to the multi-body kinematic model built in step 1 to obtain the matrices of cutter location points and tool orientation vectors;
• step 3:
• solving transformation equations of every motion axis of the machine tool and cutter location point coordinates according to the matrices of cutter location points and tool orientation vectors;
• step 4:
• building a corresponding relationship between the cutter location point coordinates and every motion axis of the machine tool based on a geometric level, and solving specific values of C-axis rotation angle of milling head and C2-axis rotation angle of the turntable;
• wherein step 4 comprises the following substeps:
• S1. extracting cutter location point coordinates comprising cutter contact point coordinate (x,y,z) and the tool orientation vector (i,j,k) from a tool path of machining a propeller in CAM software, and measuring a distance between the coordinate point and workpiece coordinate origin to obtain the offset distances of CLX, CLY and CLZ in X, Y and Z direction in world coordinate system (WCS);
• S2. measuring and recording the distances between tool setting position coordinate and workpiece coordinate origin after configuring each axis of the machine tool in CAM machining simulation software to obtain the offset distances of MLX, MLY and MLZ in X, Y and Z direction along the machine tool coordinate system;
• S3. establishing a geometric map for CLX, CLY, CLZ, MLX, MLY, MLZ, cutter contact point coordinate (x,y,z), B-axis rotation angle β of milling head, C-axis rotation angle θ1 of milling head, rotation angle θ2 of the turntable and displacements of gantry machine tool linear axes (Y-axis and Z-axis), wherein the geometric map is comprised of two parts:
• the map in XY plane and YZ plane in machine tool coordinate system;
• S4. establishing formulas of parameters based on the geometric map, to obtain the relationship between the rotation angle θ2 of the turntable and C-axis rotation angle θ1 of the milling head;
• S5. substituting the relationship between the rotation angle θ2 of the turntable and the C-axis rotation angle θ1 of the milling head into the transformation equations of every motion axis of the machine tool and cutter location point coordinates in step 3 to obtain the function equation expression of motion of each axis of the machine tool.