Design And Analysis Of Crossbeam System For High-rail Bridge Gantry Milling Machine

In order to meet the processing requirements of large and complex space curved surface parts,high-rail bridge gantry milling machine adopts the structure design of moving beam and static worktable,which adapts to the development trend of high efficiency and high precision of modern CNC machine tools.As the key component of high-rail bridge gantry milling machine,the crossbeam system includes the main moving parts such as beams,slides,rams and spindles,which have an important impact on the working performance of machine tool.In order to overcome the shortcomings of the design methods such as experience or analogy used in traditional crossbeam design scheme,GMS2516 high-rail bridge gantry milling machine developed by the enterprise was taken as research object in this paper,its crossbeam system was designed and analyzed.The main works of the thesis are as follows:(1)The overall scheme design and 3D modeling of high-rail bridge gantry milling machine were completed.Then,ANSYS Workbench was used for simulation analysis of the key components of the crossbeam system to obtain the performance index values under actual working conditions,which provided reliable data support for determining the structural design scheme with the optimal comprehensive properties in the subsequent optimization design.(2)Aiming at the multi-factor and multi-level structural design features of the key components of crossbeam system,othogonal experimental method was used to carry out the structural design of candidate scheme.Under the premise of ensuring the accuracy of the experiment results,the number of experiments was reduced and the work efficiency was improved,which lay a foundation for the implementation of multi-objective decision-making methods for crossbeam design schemes.(3)The multi-objective decision-making method respectively based on quality function deployment method,grey relational analysis method and fuzzy comprehensive evaluation method was used to optimize the crossbeam structural design scheme.The performance parameters of crossbeam structural scheme determined by the three methods were compared.The comparison results show that the comprehensive evaluation method is the best,the gray correlation analysis method is the second,and the quality function deployment method is the final ranking.(4)The fuzzy comprehensive evaluation method selected was also used to optimize the structural design of slides and ram.Further,Sensitivity analysis method was used to determine the main structural design dimensions of the key components of crossbeam system so that Lightweight design was realized.(5)The selection calculation of ball screw and motor in the doubledriven synchronous control of the crossbeam moving was completed.And the realization method of double-driven synchronous control function of the Gantry gantry axis based on Siemens 840 D was presented,which was proved that it could be more convenient and effective to realize the double-driven synchronous control of the crossbeam moving by experimental data analysis.And the synchronization error value is small,which can meet the high precision requirements of crossbeam feeding for the high-end CNC machine tool.After optimizing the structural schemes of the key components in the crossbeam system and optimizing the main structural dimensions,the overall mass of the crossbeam system is reduced by 19.3%.The maximum deformation of crossbeam system under the symmetrical milling conditions is reduced by 86.09?m,the maximum stress is reduced by 9.77 MPa,and the first-order natural frequency increased by 34.6%.The static and dynamic performance of the crossbeam system is significantly improved,and the crossbeam feeding synchronization control accuracy is high.At present,the crossbeam system structure scheme using the optimized design method in the paper has been adopted by enterprises,and the prototype of GMS2516 high-rail bridge gantry milling machine is being tested.