Research On Prediction For Drilling Force By Finite Element Method

Cutting force in metal cutting process, one of the main physical phenomena, it is direct effects on cutting heat generation, the tool wear and durability and the workpiece processing quality. Also the calculation of power consumption, cutting force, machine tools, cutting tools, fixture design and tool optimization of geometrical parameters, cutting force has a very important significance. Therefore, based on the advanced cutting force detection means and computer numerical analysis techniques, to establish the mathematical models of cutting force, to clarify accurately the value and influence of cutting force in the cutting process would facilitate the analysis, and play an important significance in the production practices.The prediction of cutting force, introduced three ways: First, the theoretical formula of cutting force. Theoretical formula has the advantage of reflecting the inherent factors among cutting force, which is helpful to analyze problems; due to simplifying a number of conditions during the derivation of a formula, the drawback of which is various greatly with the actual situation, some parameter values is still difficult to determine, in theory. Thus the calculated cutting force value and the actual results have considerable error. Therefore, it can only be used as an analytic, rather than a practical formula. Second, making regression analysis based on experimental measurements, to derive the empirical formula of the cutting force. Currently in practical applications, the calculation of cutting force is mostly by empirical formula. However, this method usually ignores the impact factors that are difficult to quantify, there is a large difference between predicted results and actual. Therefore, it usually used in estimate. The third method is based on Deform 3D finite element prediction. Existed studies have shown that the finite element method is an effective means of researching the cutting process. To this end, the author has simulated the drilling process by using the finite element simulation techniques.Based on the theory of finite element method, the important technology of cutting model is summarized, including material model, chip separation, friction model, energy dissipation and the local heat transfer, mesh distortion and remeshing. Considered characteristic of drilling process and Deform software, the finite element model of three-dimension fit for drilling process is built. The nonlinearity of material is simulated by considering the temperature effect on material physical and mechanical property and the change of flow stress that depends on the plastic strain, strain rate and temperature. The forming of chip is simulated by element deletion and adaptive remeshing technology in Deform; the finite element methods of Arbitrary Lagrangian Eulerian formulation is adopted for deal with the problem of geometry nonlinearity in drilling process; shear friction model is adopted for simulating the friction problem in cutting. The finite element model is established and the law of machining parameters on cutting force in drilling process is studied.In order to verify the correctness and feasibility of prediction based on Deform 3D cutting force, a series of cutting forces experiments are done by YD-21/4 type dynamic strain gauge. Compared experiment with simulation results, predicted values and experimental values of cutting force has reasonable consistency and common trends. Be subjected to the impact of calculated conditions, the cutting force curve in the chip separation would produce a certain beat.The finding of paper shows that cutting force prediction based on the finite element method is an efficient, cost-effective prediction method. From which we can see the idea and methods of this thesis are feasible, the results are reliable.