机械

龙门结构是龙门式机床重要支承部件,它的的动态特性直接影响到机床的加工精度。利用Solidworks2008和ANSYS10.0软件对某型号龙门铣床龙门结构进行三维实体建模与模态分析,得到了此结构的模态分析结果,即模态频率和各阶振型。分析了模态频率和各阶振型对此龙门动态特性影响,结果表明它的一阶频率在工作频率范围内,将会产生机床共振现象,影响加工精度。从龙门结构前三阶振型看,无论左右摆动、前后摆动,还是绕竖直中心轴扭动,都直接影响加工精度和切削性能,而四、五、六阶的振型对加工性能影响较小。为此,要修改龙门结构,使低阶模态频率相应提高,以提高结构的动刚度。ANSYS结构模态分析为此机床的改进设计提供了理论依据。

Gantry is an important support part of a gantry machine,its dynamic characteristic will directly affect the machining precision of the machine. 3D model of a gantry type milling machine's gantry was established by solidworks2008,the modal performances which are modal frequencies and modes were analyzed by means of ANSYS10.0 ,the influence of gantry on dynamic performance has been studied,the results show that it's first frequency is in the working frequency range,it will affect machining precision. From the first three modes,whether swinging from side to side,back and forth,or twisting around vertical axis,the machining precision will bereduced ,but the fourth、fifth、sixth mode of vibration have a little influence on the machining behavior.In order to improve dynamic stiffness of the gantry,the lower frequencies must be improved through modifying the structure of the gantry.The modal analysis based on ANSYS offers bases for the renovation and design of the machine.