Dynamic Optimization Design of Machine Tool Based on Modal Flexibility and Energy Distribution

doi:10.3901/JME.2018.23.192

Abstract

Abstract: To minimize the maximum compliance at cutting point across all working frequency ranges is the requirement for machine tool to achieve minimum chance of machining chatter and high precision machining, which is also the objective that dynamic optimization design of machine tool should be attained. A dynamic optimum method that aims at decreasing the compliance at cutting point is developed and analyzed according to the principles of dynamic optimization design based on modal flexibility and energy distribution for machine tool. By the relationship between compliance and modal flexibility to indicate weak modals, focusing on the weak modals, the energy distributions of components and links are analyzed to determine the weak parts and links, the optimum design can be realized by improving the design parameters of corresponding parts and links under certain constraints. For a universal tool milling machine as an example, based on modeling analysis and computation of machine tool, the specific application of the optimization method are described. By calculation of modal flexibility and energy distribution, the weak link of the machine is judged to be the system consisted of crossbeam and horizontal spindle body, the optimization of mass and stiffness can be realized by improving design parameters of the weak link, the optimized static flexibility and modal flexibility are greatly reduced, while natural frequencies are increased correspondingly, and the maximum value of compliance at cutting point decreased by nearly 18%. On this basis, the structure improvement design is carried out, and the comparative results of harmonic response analysis and the cutting test between the original and improved machine tool demonstrate that the dynamic characteristics of machine tool are effectively improved and cutting stability for regenerative chatter is greatly increased.

Key words: compliance at cutting point, energy distribution, machine tool, modal flexibility, optimization design, regenerative chatter, structure improvement

CLC Number:

TH113
TG502

LIAO Yongyi, LIAO Baiyu. Dynamic Optimization Design of Machine Tool Based on Modal Flexibility and Energy Distribution[J]. Journal of Mechanical Engineering, 2018, 54(23): 192-198.

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