Research On Roll Forming Limit And Coupling Relationship Of Curved Rotary Shape Cylinder

With the rapid development of modern manufacturing,curved-rotation cylindrical parts are widely used in aerospace,military and civil industries.For example,projectiles,oil drill pipe joints,oxygen cylinders,etc.,the final state of these parts is the curve rotation shape or it needs to be made into a curve rotation shape cylinder during the forming process.The existing processing methods are difficult to meet the high material utilization rate and processing The need for short time and low cost to process the curved shape of the cylinder curve.Using DEFORM-3D finite element simulation software to numerically simulate the different forming parameters of the roll forming process,the effects of parameters such as workpiece deformation,friction coefficient,punch fillet,and roller radius on the roll forming limit were studied to stabilize the roll Multi-factor coupling relationship and law of forming,establish roll forming limit charts with different process parameters;compare roll forming with traditional process drawing.the result shows:The factors affecting the roll forming limit are completely different from roll forging;the forming limit of roll forging is whether the forging can bite in,and the roll forming limit is that the bottom of the cylindrical part is penetrated(punched)or the wall is thinned and broken.When the amount of deformation of the wall of the blank is large,and the bottom is thin,the problem that the bottom of the cylindrical member is penetrated mainly occurs.When the deformation of the wall of the blank is very large and the bottom thickness is thick,the problem of fracture after the wall is thinned mainly occurs.When the deformation amount of the blank wall is moderate and the bottom thickness is thick,roll forming can proceed smoothly.With the reduction of the ratio of the billet wall thickness to the bottom thickness after deformation,the amount of wall thickness deformation that can be smoothly performed byroll forming increases.When the ratio of the billet wall thickness to the bottom thickness after deformation reaches 0.5,the roll forming can be smooth The amount of wall thickness deformation is no longer increased;as the friction coefficient between the punch and the blank increases,the friction between the punch and the blank can be increased,and the force of the punch on the bottom of the blank can be reduced,which can increase Roll forming limit;as the friction coefficient between the blank and the roller decreases,the flow resistance during forming can be reduced,which can increase the roll forming limit;the radius of the roller increases,and the contact area between the blank and the roller can be increased.That is,the contact area between the roller and the positive pressure between the blank and the punch is increased,thereby increasing the friction between the punch and the blank,and reducing the axial tensile force of the blank wall,which is beneficial to the smooth roll forming;When the fillet of the punch is less than or equal to 10,the blank is punched and is not easy to form.Due to the increase in the radius of the fillet,the stress concentration in the corresponding part of the blank is reduced.Compared with the traditional process of drawing and drawing,the weight of the blank can be reduced by 28% through the roller process,and the amount of reduction will increase as the length of the outer wall of the curved-revolving cylinder increases.Roll forming force can be reduced by about 50%.As the friction between the roller and the blank is reduced,the life of the roller mold is greatly improved.The roll forming mold is complicated,and the manufacturing cost is higher than that of traditional drawing and forming.When forming a cylinder with a different curved shape,it is only necessary to replace the roller.The operation is simple and convenient,and it is suitable for mass production.The accuracy of the established roll forming limit diagram is verified by the experimental method,which provides a basis for the development of the roll forming process of the curved-rotation cylindrical parts.