Cutting Force Modeling And Analysis In Axial Contour Turning With Self-propelled Rotary Tool

Contour-shaped workpieces have become increasingly widespread used in the bio-medical, aerospace, automotive and other fields. With the development of these fields and industry apartments, more and more high strength, high wear resistance products are needed. In such conditions, the wear resistance of conventional tool can not meet the requirement of production. If one can provide a cutting scheme, it does not have to reduce the cutting efficiency, but can decrease the cutting temperature, pressure in the cutting zone. Then, the self-propelled rotary tool can be used to enhance the productivity rate of the cutting process by using the existing tool materials (such as high-speed steel, hard alloy, etc).The difference between self-propelled rotary tool and conventional tool is that, the self-propelled rotary tool is a single degree-of-freedom mechanism. By using the self-propelled rotary tool, tool's life can be increased; the cutting efficiency and the quality of the finished surface can be significantly improved. Therefore, this thesis presents a cutting scheme in which the self-propelled tool is used to machine axis contours.The contours can be divided into three types: axial contour, radial contour and axial-radial contour. This thesis mainly focused on the axial contour, studying how to establish the cutting force model and dynamic model for using the self-propelled rotary tool to machine axis contours. By studying the effects of the tool geometry parameters and the cutting parameters on the cutting forces and the dynamic stability of the system, this thesis presented the theoretical basis for further research in the following aspects: (1) the research on the prediction of machining error; (2) the research on the prediction of tool geometry and cutting parameters; (3) the research on the prediction of system dynamic stability. The cutting force model is required to describe the relationship between the cutting force and the cutting parameters, tool geometries in the machining. So one can arrange various cutting parameters and tool geometries reasonably in the machining to increase the productivity rate and get better quality of the finished surface. The research topics of this thesis are presented as follows:1. It is considered that the cutting force is proportional to the cutting area in the machining. Then this thesis mainly established the cutting area model for using the self-propelled rotary tool to machine the axis contours considering the relative vibration between the workpiece and the tool.2. According to the research by Reddy and DeVor, this thesis established the cutting coefficient model of contour turning. Considering the characteristics of the self-propelled rotary tool, there must be friction between the rotary cutter and the bearing in the machining. Therefore, the cutting coefficient model was modified.3. This thesis has established the dynamic model for using the self-propelled rotary tool to machine axis contours, carried on the dimensionless quantity method and evaluated the vibration equation. It has laid the foundation for analysis in the next step.4. The effects of the tool geometry parameters and the cutting parameters on the cutting forces and the dynamic stability of the system were studied through MATLAB analysis.Through the above work, the following conclusions were got:1. The rake angle of the self-propelled rotary tool has a greater influence on the radial force F y, but has little influence on the cutting forces Fx and Fz .2. Inclination angleλis one of the important parameters of the self-propelled rotary tool. With the increase of the inclination angle, the cutting forces Fx,F yand their amplitudes are significantly increased, but there are few changes to the cutting force Fz .3. The tool radius has the same effect on the three cutting forces. With the increase of the tool radius, the cutting forces and their amplitudes are significantly reduced.4. The depth of cut has the same effect on the three cutting forces too. With the increase of the depth of cut, the cutting forces and their amplitudes are significantly increased.This thesis has established the cutting force model for using the self-propelled rotary tool to machine axis contours. The analysis results showed the correctness of the established cutting force model, laid the theoretical foundation for further research and had a strong practical significance.