Development of a five-axis postprocessor system with a nutating head

A postprocessor capable of converting the cutter location data to machine control data is an important interface between the NC programming design and manufacture. Owing to the fact that current research on multi-axis postprocessor methods only deals with machine tool configurations whose linear and rotational movements are orthogonal, this study has presented a postprocessor algorithm for the five-axis machine tool with a nutating head whose rotational axis is in an inclined plane. The nutating head has great advantages over other heads because it has no motors on the head where the motors for the spindle are on the machine, and the motion is transferred to them by hollow shafts and gears. The machine tool's form-shaping function matrix is derived based on the homogeneous coordinate transformation and the forward kinematics. The analytical equation of NC data is obtained by the inverse kinematics and the form-shaping function matrix. A window-based postprocessor system written by Borland C++ Builder was developed according to the presented algorithm. A five-axis machine tool with a C-axis behind a B-axis nutating rotary head is selected as an example. Through the verification by the commercial solid cutting software VERICUT®, the feasibility of the proposed postprocessor methodology is demonstrated.