Research On Shape Quality Of Hole And Punch Structure In Hole Punching Of Medium Thickness Plate

Hole punching of medium thickness plate, using die punch hole of required shape on the medium thickness plate in the press, is the method of punching processing. However,due to limitation of the process, the quality of punching is lower than drilling. Researching on improve quality of punching is becoming more and more important. Because of the punching process with mold in the press, the structure of mold has certain impact on the quality of punching. So, researching quality and die structure of medium thickness plate have an important significance on applications.In this paper,the shape precision of punching and the die structure of medium thickness plate are analyzed and researched by FEM and experiment.The main research contents are as follows:(1) In order to research the mechanism of punching medium thickness plate, the numerical simulations of punching medium thickness plate conventional clearanceare carried out.The finite element analysis molds of punching conventional clearance are established.The distribution of stress is obtained, when the plate is cracking, developing and fracturing.The deformation mechanisms of punching medium thickness plate conventional clearance are explained.The concentration area of greatest stress is appeared on the edge of punch in punching process.Found and summarizes the problems and reason in the conventional punching.(2) Aquality standard that measure the shape precision of punching is put forward and established after comprehensive reflectsinfluence extent of burnish and corner collapse to punching quality. The shape precision of punching is the product of length of burnish ratio thickness and cosα(α is the corner collapse of fracture). It is show that the greater the value, the better the quality, by mathematical analysis study of the shape precision of punching. Researching the influence law of process parameters and blank holder to the shape precision of punching by experiment and FEM.(3) In order to improve the quality of medium thickness plate punching, a new die structureis put forward. The numerical simulations of punching medium thickness plate are carried out.The deformation mechanisms of punching medium thickness platenew diestructureare explained. Optimizing new punch diestructure by using orthogonal experiment, the optimal experimental scheme and the worst orthogonal are obtained. Comparing analysis of the worst testing scheme of punching shape quality is higher than conventional punching, thus improvement of new punch diestructure is effective.(4) In order to study the new mold is feasible in the actual production, we designedexperiments. Throughexperimental scheme, the experimental results of new die structure and conventional clearance are obtained.Comparing analysisquality of new diestructureexperimental results is higher than conventional punching. The result of experiments proved that the new die structure can improve quality of punching.In summary, the conventional die and the new die of punching medium thickness plate is researched in this paper, and the mechanism of punching medium thickness plate is explained.The quantitativeformula of the shape precision of punching is established and the curve of allowable load is put forward.The influence oftheclearance-diameter ratio, relative clearance and the blank holder direct at the shape quality of punching are researched by using experiment and numerical simulation. The new die structure can improve the quality of punching is put forward,and the mechanism of new punching and parameter optimization and experiment are researched,and the new die structure can improve the quality of punching are further verified.In this paper, the research results have an important theoretical significance and application value to measure and improve punching quality of medium thickness plate.