Cutter Swept Volume Modeling And Simulation For Multi-axis NC Machining

With the development of computer technology and manufacturing equipment industry, CAM (Computer Aided Manufacturing) as an important tool of modern manufacturing technology, has become a symbol of national core-competitiveness of manufacturing industry. As an important part of CAM and an important means to improve the production cycle, multi-axis NC machining simulation technology is always a research hotspot. In this paper, the interrelated theories and key technologies, such as the cutter swept volume modeling, the determination of cutter velocity, collision check and machining error detection, are studied combined with practical projects. And a software prototype system is developed.The disadvantages of traditional cutter swept volume calculation method are computational complexity and lack of general. For these problems, the APT cutter swept volume modeling and solving have been investigated. Based on envelope theory, the modeling method of cutter swept volume, swept envelope and instantaneous swept profile is proposed by the analysis of cutter swept volume forming process. By integrating the intermediate swept profiles, the cutter's swept envelop can be constructed. An APT cutter is represented by a sphere model of revolution solid. The cutter's instantaneous swept profile modeling and solving is finished by the decomposition of cutter surface. There are different models for the calculation of cutter instantaneous swept profile in each part of cutter surface.The velocity determination of cutter on multi-axis NC machining is always the key technology of the cutter swept volume determination. The rotational axis on multi-axis machining will affect the linear velocity of cutter surface The cutter motion form is studied in multi-axis NC manufacturing. The cutter velocity of CL data is determined by the research methods of computer graphics. On the basis of machinery kinematics theory, machine tool kinematic structure model is proposed and the transformation matrix representing the transformation of cutter to workpiece, which is used to calculate the cutter velocity of NC code. Finally, the feasibility of the method is validated by two examples, one of which is a machine tool with immovable workpiece, the other of which is a machine tool with movable workpiece.The machining error detection of simulation result is one primary goal of machining process simulation. Based on the in-depth study of workpiece machining error detection with discrete vectors, the comparison between simulation result and design part model is carried out by the data of simulation. In the view of the low efficiency of intersection calculation between normal vector and part, the machining error detection algorithm based on composite discrete vectors is proposed with accuracy and efficiency.In conclusion, according to the research work and achievements, multi-axis NC machining process simulation software prototype system is developed with the development tool, VC++6.0, ACIS R16 and HOOPS 1220. The functions of this system include CL data-based machining process simulation, NC code-based machining process simulation, interference and collision check machining error detection and etc.