The Mathematical Model Of Drilling Force And FEA Of Gun-drill With Planar Flank

With the rapid development of manufacturing, deep-hole machining occupies more and more proportions in hole-machining field. Its demand is becoming larger and larger. As the most popular deep-hole machining tool, gun-drill is fit for small and medium deep-hole machining. Due to the low strength and rigidity of gun-drill, once the chip removal has trouble, the drilling forces will increase sharply, and the drill rod will blind, resulting in severe vibration. It will cause tipping of the drill head easily.In order to increase gun-drill's economy, quality and stability, this thesis has four parts, based on the analysis of gun-drill's drilling forces.Firstly, basing on gun-drill's structural feature, cutting principle and micro-tools theory, the mathematical model of drilling forces is established.Secondly, we solve the values of drilling forces and torques machining HT250. Compared with values given by reference [4], the results are proper. Analyzing the mathematical model of drilling forces by Matlab, we obtain the curves of drilling forces and torques,which relate the machining parameters and geometry parameters such as external angle, inner angle, amounts of feed and so on. The ranges of the parameters are also given.Thirdly, gun-drill bears pressing, bending and twisting deformations equaled as a free beam. We establish its mechanical model and verify it.Finally, we do the FEA of gun-drill by ANSYS Workbench. Using the orthogonal test, we analyze the parameters by Von-Mises stress's and maximum deformation's and get the optimal combination of external angle, inner angle, first-clearance angel of external cutting edge and width of external cutting edge. Changing amounts of feed and wearing widths of flank individually, we compare the results with gun-drill's strength and rigidity.This thesis not only supplies some theory references for forecasting drilling forces but also provides a new type of design methods for optimizing design of gun-drill. It simplifies design procedures, shortens design cycles and reduces the cost.