Theoretical-Experimental Modeling Of Milling Machine For Researching On Dynamic Characteristics

High speed milling process can effectively reduce the cutting force and can improve a machined surface on the workpiece. High speed milling is an effective measure of improving production efficiency and processing quality. Since the periodic variation of the process and the cutting force, it can cause the vibration between the workpiece and tool. Chatter can happen when the vibration generated at the natural frequency. Productivity of high speed milling operations can seriously limited by chatter occurrence. Chatter vibration can imprint a poor surface finish on the workpiece and can damage the cutting tool and the machine. Chatter occurrence is strongly affected by the dynamic response of whole system, i.e. the milling machine, the tool holder, the tool, the workpiece and the workpiece clamping fixture. Tool changes must be taken into account in order to properly predict chatter occurrence. Recently as the machine tool is developed with the trend of high speed, high accuracy and high efficiency, dynamic characteristics of machine tool have been becoming increasingly demanding.ZX20series light column vertical milling and drilling machine was studied in this paper. The dynamic characteristic of machine tool was studied through theoretical-experimental method. Analyze and verify the method by contrasting the modal test results. The main contents of this paper are as following:Firstly, a model of the milling machine-tool is proposed:the machine frame and the spindle were modeled by an experimentally evaluated modal model, while the tool was modeled by a discrete modal approach, based on the continuous beam shape analytical eigenfunctions.Secondly, dynamic test is conducted on the ZX20light column vertical milling and drilling machine, its parameters of modal of machine frame and the spindle and whole machine tool are acquired respectively.Third, Build the Finite Element Analysis model of CAT40joint:analyze nonlinear contact, thorough research is done on the regularity of pretightening load to find out how it influence joint deformation.Fourth, the semi analytical method which was used to estimate the contact stiffness at the spindle-tool holder interface of CAT40was proposed. Effectiveness of the proposed method was validated by the experimental data in the reference document.Finally, ZX20light column vertical milling and drilling machine was studied. The contact stiffness at the spindle-tool holder interface was estimated. And the equation of motion was obtained. This paper proves the correctness of the theory contrasting the experiment data.