Error Compensation For Propeller Machining Considering Geometric Error Of Machine Tool And Machining Error Of Blade Surface Based On On-line Measurement

The propeller is the core component of the normal operation of marine propulsion and a typical representative of marine engineering equipment.Its manufacturing level directly affects the independent development of China ship-building industry.In order to meet the high-precision processing requirements of the propeller,all stages of the entire process chain need to maintain a high degree of accuracy.At present,as the size of the machined components becomes larger and the structure becomes more and more complex,the machine tool is also developing in the direction of large-scale and multi-axis.Accordingly,the geometric error of the machine tool has an increasingly greater influence on the machining accuracy of the end workpiece.Therefore,for the processing of the propeller,the error compensation of the machine tool for processing is imperative.In addition,tool wear,and the deformation of the tool and workpiece during machining have caused the machining error of the propeller blade,which greatly limit the improvement of the propeller machining accuracy.For the model structure and processing requirements of multi-blade propellers,work preparation and process arrangement in the pre-processing stage.The machining of 1:10 multi-blade propeller is completed on GMC 1600H/2.And GLOBAL CLASSIC SR 7.10.7 is used to measure the machining error of the finished propeller.Aiming at the sensitivity analysis of the geometric error of GMC 1600H/2,the kinematics modeling of the machine tool with parametric geometric errors was performed.The derivation process of the coordinate conversion matrix in the kinematics modeling process of the multi-axis CNC machine tool is analyzed,and the error matrix for the comprehensive parameterized geometric error of each axis is established.The general kinematics model of the machine tool considering geometric errors is established according to the topological relationship of the machine tool.Then,an example modeling is carried out for the propeller processing machine tool—GMC 1600H/2.Finally,through the orthogonal test,the primary and secondary sequences of the geometric error of each axis of GMC at different levels are analyzed to reduce the calibration numbers of geometric error.In order to achieve the calibration and compensation of the geometric error of GMC,the geometrical error calibration of the linear axis and the movement axis of the machine tool was performed using a laser interferometer and a laser tracker,and the geometrical errors are parametrically fitted.Geometric error compensation is performed based on a welldefined kinematic model with geometrical errors in GMC.The ideal tool location datas in propeller machining are used as input to verify the effectiveness and convergence of the error compensation algorithm.Finally,the accuracy of the error compensation algorithm is proved by processing experiments on GMC 1600H/2.In order to achieve the optimization of propeller blade surface machining,the surface of the propeller blade is measured on-line to obtain the machining error and the surface is reconstructed by replacing the original propeller blade surface with the reconstructed surface.The on-line measurement of the propeller blades obtains data points,preprocesses the data points,and then uses the software called Geomagic Studio to perform curved surface packaging,surface fitting,boundary editing,deviation analysis,and other processing to obtain reconstructed surfaces,successfully importing the reconstructed surfaces into UG machining tool path generation and experimental verification.