Predicted Study Of Tool Deflection Error For Milling Of Variable Curvature Surface Of Hard Mold Steel

For mold industry, the techniques of finish of mold steel after harded are adopted gradually. As tool deflection error of hard machining is protruding and it influences the polishing time directly during mold production. And this would result in longer producting time and higher producting cost. Therefore, the study of tool deflection error is significant and necessary. Based on the questions above, this paper studies the tool deflection error of variable curvature surface with the purpose of providing guidance for reasonable processing technic, improving production efficiency and decreasing production cost.The main issues of this paper regarding tool deflection error of variable curvature surface are following:Slot cutting experiment is operated with multi styles cutting parameter method of planar slot cutting average milling force. No matter from the view of the trend or the value, the experiments prove the milling forces obtained by simulation to extremely coincide that obtained by tests. The results show that simulation results coincides with experiment results well.Taking different types of curvature surfaces, including concave surface and convex curved surface, this paper studies the influence of curvature radius and inclination angle on start/exit radial immersion angles and axial position angles. In the experiments, the model of contact area between cutter and workpi ece is obtained with analytical geometry method. Based on instantaneous cutting force model, complete model of milling force under workpiece coordinate system is obtained by coordinate conversion and integral method. The milling force model is carried simulation with Matlab simulation software. And the simulation model is proved to be accurate and reliable through the comparison between the milling forces obtained by simulation and that obtained by tests.Study of deflection of tool system is carried out. The three stage type of cantilever beam, which can more actually describe the deflection caused by the force tool system bear, is obtained by the improvement of traditional two stage cantilever beam. And the finite element stimulation of deflection of tool system is carried with ANSYSWorkbench and compared with the model of three stage type of cantilever beam mentioned above. The result of the comparison shows that the model of three stage type of cantilever beam set up in this paper can accurately describe the deflection of tool system under certain milling force, providing theoretical principle for subsequent research.Regarding to the milling of variable curvature surfaces with ball-end mills. The researches of tool deflection error are carried out under various conditions, such as equal curvature with different inclination angles and different curvature with same inclination angles. And these researches are tested and verified by experiments. The results show that the method can efficiently predict the to ol deflection of variable curvature surface machining.