The Precision Design Of CNC Machine And Research On Its Consistent Product Information Model

Domestic and overseas scholars have made a lot of researches on CNC machine precision and put forward a series of error modeling and measurement method,which has made a great achievement,but can not meet requirement for integrality and practicability of precision design.This article is supported by the national scientific important programs named "high-grade CNC machine and basic manufacturing equipment" and national natural science foundation of china named "consistent theory of product information modeling and research on precision chain design method of complex equipment",and proposed precision modeling method of machine based on topological transitivity,then built precision model of CNC grinding machine and studied its consistent product information model.This article identified the lower body array of CNC guideway grinding machine’s topological structure and buit CNC grinding machine geometric error model containing 21 items of comprehensive geometric errors on this basis,then introduced the principle of processing and separating errors using 9 line method.Taking bed-worktable guideway as example,the mathematic relation between geometric error distribution of guideway and tolerances of parts were described respectively based on jacobian small displacement torsor theory and multi-body system theory,and they were compared and analyzed,then tolerances were optimized using genetic algorithm on the stage of precision design.In allusion to tolerance coupling problem,this article proposed a method of handling the coupling between straightness tolerance and size tolerance based on monte carlo simulation and response surface method,which provides a basis for handling coupling problems between other types of form tolerances and size tolerances.According to changes and constraint inequalities of small displacement torsor parameters,the bandwidths of small displacement torsors’actual change interval were simulated based on monte carlo method and the response surface models of bandwidths were generated based on response surface method,and the result indicates that the maximum descend of bandwidths of small displacement torsor’s actual change interval compared with that of theoretical change interval is 10.9%,and bandwidths of error distribution ranges decrease partly considering coupling between straightness tolerance and size tolerance,which improves the efficiency of precision design.This article studied the method of building CNC machine consistent product information model on the basis of precision design and analysis on CNC machine precision modeling,requirement for product information consistency was concluded,and the method of realizing geometric data consistency based on skeleton model technology was raised.On this basis,the function and usage of precision analysis and optimization module were discussed,which provides theoretical foundation for building CNC machine model possessing product information consistency.