刀具频响特性测试的边界条件选取

Frequency response function (FRF) testing of endmills under free-free boundary condition is one of steps to acquire the tool point FRF of the machine tool assembly by substructure coupling method. Two boundary conditions, suspended by elastic string and supported by flexible foam, are explored to compare the difference of tested FRF on three endmills. The FRF of a standard round bar is theorical calculated and measured to validate the experimental method. The results show that the difference of FRF caused by the two boundary conditions is negligible, and the maxmium error of the first natural frequence measured is only 0.05%. It's better to employ flexible foam as the boundary condition in impact testing of tools for the sake of efficiency.