Research On Post-processing Technology For Five-axis NC Machine Tool

Five-axis NC machining is the important method to achieve high efficiency and quality machining for complex curved surface parts.Post-processing Technology is the bridge to connect CAD/CAM and five-axis NC machine tool and a key technology to realize five axis high-efficiency machining.So,it has a great theoretical significance and application value to research post-processing technology for five-axis NC machine tool.The paper takes spindle horizontal type AB two turntable five-axis NC machine tool as the research object.Then analyzes the structure and kinematics relationship and establishes the kinematics model of the machine tool.The post processing algorithm to convert the cutter location data into the movement for translational and rotational axes of the machine tool is deduced based on the theory of homogeneous coordinate transformation and the matrix transformation.For the singular problem generated by drastic motion of rotation in post processing singular area inverse solving rotation angle,The paper analyzes the relationship between the angle of AB step and the space angle between the unit tool axis vector and the taper cone degree,and reveal the mechanism of singularity problem with an analogy of AB axis motion to the AB step on the surface of sphere formed by the end of the cutter axis vector in space.Projecting and local zooming the tool axis vector,the range of singular area is detected and defined by analyzing the distance relation between the projection orientation line and the singular area.The B step is decomposed outside the singular area by the cutter location point and tool vector interpolation and the singular problem in post processing is eliminated by the method of replacing the cutter data in singular area with no singular problem cutter data.The paper analyzes the APT file format generated by CATIA and the key command statements in the processing information.Based on the development platform of IMSpost general post processor,develop the special post processor for GROB GA550 two turntable five-axis NC machine tool which can realize the conversion from APT file to NC program.The virtual simulation machining system of GROB GA550 five-axis NC machine tool is established based on VERICUT simulation platform.The shell part is selected to process programming based on the main production tasks of the CNC machine tools and generate NC program by post processing.The accuracy of post processing is verified by the comparison between virtual simulation machining and the actual machining of the shell part.The interpolation processing software accomplishing singular problem avoidance strategy was developed.The cutter data without singular problem obtained by solving the cutter data which produced from curved surface parts with quadratic interpolation in software.Do virtual simulation machining,compared the machining effect with the parts which was not solved by interpolating software.The verification of machining simulation results show that the singular problem avoiding strategy proposed of the paper could effectively eliminate the singularity problem in post processing and achieved high efficiency and quality machining of the machine tool.The research achievements was been applied to the actual production.