Dynamic Characteristics Research Of Active Pole Horizontal Machine Center

This paper is focused on the dynamic characteristic of Pole active horizontal machine tool with forced vibration test in real operation. In addition, a comparison between the test result and the FEM analysis has been conducted. Based on the result of the comparison, the dynamic characteristic of pole active horizontal machine tool is the superposition of substructure resonances in forced vibration excitation has been realized.The project is derived from the National Science and Technology Major Project and the National Key Technology R&D Program. The projects names are "Machine Tool Numerial Design in static, dynamic and thermal condition (NO.2009ZX04014-034) ", "The design of VHT machine center (NO.2009ZX04001-031) ", and"The design of Gantry-type Machine Center (NO.2007BAF21B01) ".Firstly, it is introduced that the modal test method in measuring single solid structure by impulse, sweep-sine, and random signal. Considering its weakness in determining the general dynamic character in different substructure locations, a new method based on forced vibration excitation signal to test the machine tool dynamic character in different substructure locations is developed. MDH50 horizontal machine tool is used to be a typical case to make a plan for determining the pole active horizontal machine tool dynamic character.Secondly, vibration intensity has been introduced for extracting the key modes from 225 test operation modes. The resonance feature in these key operating modes by velocity-spectrum is analyzed. Thus, the natural frequencies, resonance modes, and resonance structures in the real operating stimulation are obtained.Thirdly, the FEM analysis has been conducted. In the interface joint of MDH50 machine tool, as rolling bearings and rolling guidelines, the past joints dynamic research results has been used to imitate the dynamic properties by applying the stiffness and damping coefficient into spring element in FEM model. A satisfied result has been got which showed the same resonance modes in FEM and the test. The maximum error of natural frequency between these two methods remained under 10 percent in our comparison.Finally, the pattern of pole active horizontal machine tool that its dynamic character comes from the superposition of substructure dynamic characters in forced vibration excitation has been realized. For the MDH50 pole active horizontal machine tool, the general machine tool dynamic characters is derived from the spindle-headstock component resonance and column resonance, the bed can be ignored caused by it high-stiffness property. Thus, we believe that we only need to consider the upper structure in designing the dynamic property of pole active horizontal structure.