The Optimal Design Of The Three-point Support Of T-shaped Bed Of Precision Horizontal Machining Center

As a critical supporting component of a NC machine tool, the static property of the bed have a huge impact on the machining accuracy. After the topological structure of the bed is determined, the support method adopted will play an important role in the static and dynamic properties of the bed. In recent years, the three-point support method has drawn more and more attention in the machine design field at home and aboard because it has a wealth of advantages than the prior art, such as easier leveling, higher stability, smaller internal stress and a stronger ability to maintain good machining accuracy. But there is still not clear design theory or specification about the three-point support method in China at now. Therefore, the research on the three-point support has a high application value. The major works could be summarized as follows.The mechanical model of the T-shaped bed under three-point support was established through general equivalent simplification. Based on the basic principles of the mechanics of materials, the formulas of the deformation of the key points caused by their own gravity of the vertical and horizontal beam were derived respectively. And by making each formula be equal, the solving equations to determine the parameters of the optimal three-point support location were given, which can be solved by the program edited in the MATLAB software.By taking a T-shaped bed as the study object, the multi-objective optimization of the three-point support positional parameters was carried out. During the multi-objective optimization, the building process of the multi-disciplinary simulation analysis was introduced in detail. The result of the multi-objective optimization of the optimal three-point support location was given as a conclusion at last. By utilizing the finite element analysis method, the effectiveness of the optimization result was verified.Through the utilization of the DOE method, a further study about the influence degree of each structural size on the static and dynamic performance of the bed was carried out. Then, the key structural size impacting the bed's static and dynamic properties most were found out and the interaction effect between each key size factors were analyzed. After completing the analysis above, a Kriging approximation model was created by the DACE toolbox attached in the MATLAB software. Finally, the ranges of the key structural size were given through the analysis of the Kriging approximation model.Through the work above, the conclusions and achievement can provide an initial guidance in the determination of the three-point support positional parameters and the key structural sizes of the T-shaped bed during its design phase.