Effects Of Drawing And Bulging Parts Forming Condition On Forming Limit

Metal material is the foundation of modern civilization.Plastic processing technology is a kind of manufacturing method with the longest history. With the fast development of the sheet metal stamping technology and the continuously expansion in the scope of application ,drawing process and bulging process, based on their respective particular characteristics, play a decisive role in the punching production.However, the forming of many accessories is incomplete drawing or bulging , but manifests as drawing and bulging forming property.In addition, for now, there is a shortage of comparatively further study in the aspect of drawing and bulging forming and related forming limit theory, processing parameter, and formula. According to this problem, on the basis of using a large amount of technical data for reference, taking the spherical-bottomed cylindrical cup as research object, combined with the analysis of the theoretical, physical experiment, numerical simulation, this article analyses the effect rule of blank holder force, lubrication, material thickness, deformation rate and caving die circular-arc upon drawing and bulging forming limit. Taking the cover board of centrifuges produced by some industry as an example, this article makes a further study for the problem of raising forming. Besides, this application of it has result in good effect. This paper also put forward some methods of these accessories with drawing and bulging in the process of calculating forming.A concrete analysis is made as follows:1. During the drawing processing, the stress-strain state for the semisphere-part and the cylinder shape with flanger has been analyzed in theory.2. The simulation for the drawing and forming of the cylinder shape and spherical-bottomed cylindrical cup with flanger is conducted by using LS-DYNAFORM. The influence law of blank holder force, lubrication, deformation rate, material thickness, cavity die circular-arc semester and different materials upon forming limit has been analyzed.3. Selecting the common plate Stl4 and stainless steel plate 0Cr18Ni9, by means of physical experiment, the influence of the blank holder force, lubrication, cavity die circular-arc semester and different materials upon the spherical-bottomed cylindrical cup has been analyzed.4. Based on the methods of theoretical analysis, numerical simulation and numerical fitting, the calculation equation of forming limit height for the spherical-bottomed cylindrical cup, under different forming conditions, has been deduced.5. The formula deduced is put into use in the field of calculating the forming of cover board of centrifuges.This research is able to make up for the deficiency of this theory in drawing. It also has some academic value and engineering practice significance in sheet metal stamping theory and the improvement of punching in quality. The results can be also used as a reference for engineering in quality control.