Modeling statics and dynamics of milling machine components

Official URL: http://risc01.sabanciuniv.edu/record=b1081775 (Table of Contents)

CAD/CAM systems and CNC machine tools have made significant impact on machining accuracy and productivity. However, material removal rate and quality in machining may still be limited due to issues related to the process mechanics which are not considered in CAD/CAM systems. In this study, modeling structural properties of milling system components is presented. These models eliminate the need for stiffness and transfer function measurements, and together with cutting force and stability models, they can be integrated into CAD/CAM systems to predict and compensate surface errors, and determine chatter free machining conditions. Therefore, the process is also simulated in addition to the geometry, which is usually the missing part in virtual manufacturing systems. The goal of this research is to develop a virtual machining system for precision machining of sculptured surfaces in which the part geometric errors contributed by the machine tool errors are predicted and evaluated prior to the real cutting. Cutting forces produce deformations of the tool and these cause dimensional and form errors on the workpiece. Milling forces can be modeled for given cutter geometry, cutting conditions and work material. The force prediction can be used to determine form errors on the finished surface. Chatter vibrations developed due to dynamic interactions between the cutting tool and workpiece. Chatter vibrations cause poor surface finish and inconsistent product quality. Static and dynamic properties of end mill are required to predict the form errors and chatter stability limits without measurement. In this research, generalized equations are presented which can be used for predicting static and dynamic properties of the cutting tool. The static and dynamic characteristics of tool and tool holder can be obtained by using finite element analysis (FEA). Considering great variety of machine tool and tool holder configurations and geometries, FEA for each configuration is very time consuming. In this study, the models are seemed to be accurate for prediction statics and dynamics characteristics of the tool.