Several Issues On The Structure Design Of Complex Box Precision Boring And Milling Machining Center

Precision composite boring and milling machining center as a foundation of industrial production of large equipment,plays an irreplaceable role in aviation, aerospace, shipbuilding, automobile, power generation equipment, national defense and other fields of product manufacturing,whose manufacturing precision and efficiency will directly affect the quality of end product and cost.The paper analyzing the structure characteristics of the boring and milling machine, advanced technology at home and abroad, developed with independent intellectual property rights, domestic and international leading precision compound boring and milling machining center through the combination of innovation and technology combined the original rational innovation, which studies and solves the several key problems in structural design. The concrete solution, contents and results are as follows:1.The structure and layout of the overall: First of all, we need to analysis the advantages and disadvantages of all kinds of machine tool movement and distribution form, integrated in the moving parts of lightweight, high stiffness requirements; Then the paper puts forward combining gantry structure and horizontal structure, the use of motorized spindle with mechanical shaft double spindle, single gantry composite lie the layout of the structure.2.The primary feature structure form:on the basis of the comprehensive analysis of advanced structure of boring and milling machine tools at home and abroad, combining with the calculation and analysis, we put forward the key structure of the major feature of composite boring and milling machining center, such as the center of gravity drive technology applied to the boring system, the high speed and high precision of feed system, the design of the precision rotary table. Furthermore, paper studies the vibration of the system affected the changes of the center of gravity driven screw span, finally it is concluded that under the condition of the actual working condition allowed, the larger ball screw span should try to be chosen.3.A new type of deformation compensation method, the hydraulic – lever compensation method, was used to solve the problem of flexural deformation error of the ram. First, the method of finite element analysis is used to get the ram distribution law of bending deformation of the ram, and the relation curve between the deformation and trip of the ram. Then the initial count value of the lever compensating force is calculated by the theory of mechanics of materials analysis, which combines with finite element analysis method and polynomial least squares fitting, the curve of compensated rod and ram stroke drawn. Finally through analyzing the compensation results we can concluded that with the method the ram distribution law and error of deflection and flexural is accurately forecast and obtained the ideal controlled.4.Large lathe bed parts structure design, the optimization analysis:First of all, we need to set up three different types of reinforcement plate arrangement of lathe bed structure. Through the finite element analysis, it’s focused on that how the arrangement type of steel plate and steel plate thickness affects on the static and dynamic characteristics of the lathe bed. Secondly, the analytic hierarchy process(ahp) of the comprehensive performance of lathe bed and the sensitivity analysis of the thickness of steel plate are applied. Finally, structure shows that the groined glyph steel board layout already gets good static and dynamic characteristics. Thus a reasonable choice of stiffened plate layout and size parameters of the stiffened plate is a kind of effective means to improve the lathe bed static and dynamic performance. The results can provide a reference for machine tool lathe bed and other major structural design.