Development Of General Post-processing System For Five-axis CNC Grinder And Milling Machine

Because of the difference on the the machine tool structure and the definition of the installation direction of the workpiece(the five-axis milling machine determines the Z axis direction by the direction of the spindle,but the spindle of the five-axis grinder can be any of the X axis,the Y axis or the Z axis;and the workpiece coordinate system setting,the grinding wheel installation,blank clamping and positioning and so on are also different),there are still many shortcomings in the generality of the motion solving algorithm and the post-processing system for the five-axis grinder and milling machine.For this problem,a deep research has been made in general solution algorithm,grinder process problems and system development in this paper.And a set of post-processing system software is developed which can apply to various five-axis grinder and milling machine.This paper mainly completed the following research:(1)In the research on the general solution algorithm,the structural difference between the five-axis grinder and milling machine is analyzed.The spindle direction is introduced into the structure division of the machine tool,and the division method of 36 kinds of structure is put forward,and a general post-processing coordinate system for grinding and milling is established based on this.In order to solve the problem caused by the fixed direction of the workpiece coordinate system,the concept of rotation angle of the workpiece coordinate system is introduced into the post-processing solution model,and the unified solution of machine tool motion value is realized in different coordinate system of the workpiece,and the portability of the numerical control code is improved.In view of the special machine tool with nonstandard movement positive direction,a method has been put forward in which a result is solved and adjusted according to the default positive movement direction,so that the unified solution of this kind of machine tool is realized.The spatial coordinate relationship between different types of machine tools is analyzed,and a solution method is proposed which need transforming the type of machine tools.In this method,36 types of machine tools are transformed into 6 types of machine tools with Z axis by rotating coordinate systems.Thus,the angle solving methods are reduced to 2,and the solution methods of flat momentum are reduced to 6.(2)In the research on the kinematic grinder process problems,the characteristics of the multi-step grinding process,the installation of the grinding wheel group,the blank holder positioning and the feed and cutter back method in grinding process are studied.The influence cased by the installation position of the grinding wheel,the installation direction of the grinding wheel and the holder length of the blank is analyzed.A method is proposed which use the the position bias and the direction of the grinding wheel to let the multiple cutter location files can be processed at the same time,so that the efficiency of post-processing is improved.The process characteristics of machining milling cutters and the relationship between the structure of grinder and the mode of feed and cutter back between process steps is analyzed.Through the definition of the interference detection coordinate system for grinding wheel and blank,a unified expression of the position relationship between the grinding wheel and the blank is realized.Based on this,the safe position of feed and cutter back,the rapid approaching position and the tool path is calculated and the code of feed and cutter back can be added automatically,so that the machining safety is improved.(3)In the development of the post-processing system for five-axis grinder and milling machine,the system is divided into 4 main functional modules through the detailed analysis of the function,including the rule base management module,the machine tool management module,the algorithm module and the post-processing module.The data structure is formed in many forms such as ACCESS and XML file,and the cutter location data is processed by step method including cutter location identification,function identification and function parameter extraction.The system architecture is designed with the idea of stratified construction,and it is divided into 4 layers which are database layer,persistence layer,business layer and presentation layer.Then the post-processing system software is developed with MFC and ACCESS.(4)4 machining examples are used to verify the correctness and generality of the system.The verification includes the support for various catter location formats,support for various NC codes,and support for various milling machine and grinder structures.The example processing results prove the correctness and universality of the post-processing system.