Study On Swing Mould Of Joint Swing Type Free Pipe Bending Process

High efficiency,low consumption and light weight are the development direction of aerospace and automotive parts manufacturing technology.Elbow members have been widely used in modern industry for their higher specific strength,specific stiffness,and good impact resistance.The traditional elbow components have poor adaptability and low productivity,and cannot meet the diversified and complex product requirements.The joint swinging free bending process has the characteristics of high adaptability,high efficiency,low cost,and can perform complex space bending.Tube processing,its mold design is the key technology for process realization.Therefore,this paper takes the joint swinging mold of stainless steel free bend pipe as the research object,and carries on the quality analysis of mold design and forming process.The specific work includes:First,the theoretical analysis of the process principle was carried out.The motion and stress state of the pipe bending process are analyzed.The geometric relationship between the bending radius and the bending action distance and the offset is theoretically derived.The calculation formulas of bending force and propulsion force are analyzed.Combined with the material and process characteristics,the stress and strain state of the pipe bending,forming defects,and evaluation indexes are theoretically analyzed.Then,the mold configuration is analyzed,the mold design flow and method are expounded,and the mold structure design is given.According to the characteristics of the process,two feasible swing mold configurations were analyzed,the design flow was proposed,the structure of the swing mold was designed,and the specific structural dimensions of the mold were given.Based on the elastoplastic finite element method,the stress and deformation states of the two kinds of oscillating molds during the bending process of the pipe were analyzed,and the feasibility of the design of the oscillating die structure was verified.Furthermore,through numerical simulation,the influence of the mold structure and parameters on the forming quality was studied.For the double joint double swing control mold,the influence of the radius of the die arc of the inlet fixed mold on the forming quality was analyzed,and the size of the exit portion of the exit swing mold was optimized.Aiming at the single-joint single-swing control mold,the effects of the gap and friction coefficient between the outlet swinging mold and the pipe fitting,the radius and contraction of the die arc of the inlet fixed die,and the bending action distance on the formability of the pipe are studied and optimized..Based on the results of multiple sets of numerical simulations,the minimum bend coefficient that can be achieved by the swinging mold is analyzed,and the relationship between the bending radius and the bending action distance is obtained and verified.Finally,numerical simulation and orthogonal analysis are used to comprehensively analyze the mold forming ability and quality influence law.The die shrinkage amount,the bending action distance,the offset amount,the friction coefficient and the clearance of the outlet swinging die and the pipe member,and the inclination angle of the outlet swinging die are the influencing factors,and the ellipticity and the wall thickness thinning rate are the evaluation indexes.The parameters most influential to the bending formability were analyzed.The paper has carried out the structural design and optimization of the swinging mold for the joint swinging free bending process,and has important technical reference value for the research and development of the localized equipment to promote the process.