Optimal design of the bed structure of machining center under the influence of variable load milling force

LIANG Li-qiang1, SA Ri-na1,2,3, GAO Feng1
(1.Institute of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;
2.Institute of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China;
3.Canny Elevator Company Limited, Suzhou 215213, China)

Abstract: Aiming at the influence of variable load milling force on the performance of the machine bed during the work of the machining center, the material density distribution of the machine bed and the basic structural unit size of the machine bed were studied. A multi-objective topology optimization design method was proposed, which aimed at the low-order natural frequency and minimum flexibility of the bed, and the volume fraction as the constraints. A mathematical model of multi-objective topology optimization under the influence of variable load milling force was constructed using the compromise programming method and the average frequency method. The optimal structure layout of the machining center bed was obtained according to the material removal scheme guided by the topology optimization of the variable density method. At the same time, the standard secondorder response surface of the optimized Latin hypercube sampling construction unit was used to perform multi-target genetic algorithm on the bed optimized size. The results indicate that the natural frequency of the bed is increased by 16.9%, the mass of the bed is reduced by 17.4%, the maximum deformation is reduced by 14.4%, and the maximum stress is reduced by 18.8%. This optimization scheme makes the structural layout of the machining center bed more reasonable, and realizes lightweight design.
Key words: variable load milling force; compromise programming method; multi-objective topology optimization; element method size optimization