Mechanism Study On The Extrusion Of Bending Pipe With Many Punch Actively Controlled

As a technological method of pipe plastic processing, pipe bending plays an role inindustrial production. Bending parts made with pipe, including plane bending and spacebending, has a wide range of applicant. In the process of pipe bending forming, because ofconstraint factors including process and equipment and so on, the existence of various defectssuch as medial wall thickening, wrinkling, thinning of the outer wall, rupture is inevitable. Inorder to avoid these defects in practical applicant, we study a new production process to meetthe actual production. The extrusion with many punch actively controlled to make pipebending parts, drawing the concept of multi-point forming technology, is a new technologymethod which can get a plane or space forming tube by controlling the extrusion loadingmode and the punch shape.In order to study the mechanism on the extrusion with many punch actively controlled tomake pipe bending parts, this article designs different models including double punch, threepunch, punch four, six punch model to simulate respectively. Through the analysis of thesimulation results, we find the universal laws about the extrusion with many punch activelycontrolled to make pipe bending parts.We make use of finite element method to mainly study the velocity field of the doublepunch simulation model. Plane bending tube can be prepared by constant loading, and spacebending tube can be got by variational loading mode. The velocity differential between thedouble punch is the main factor that affects the balance of the velocity filed. The size ofvelocity differential makes effect to the pipe curvature. The relationship of between thevelocity differential and the pipe curvature is that there exists the best velocity differential tothe largest curvature of the pipe. The velocity differential between the double punch is a resultof coupling of multiple factors, which is influenced by the structure of the model, the wallthickness of the pipe, the height of blanks and so on. In certain conditions, exist thecorresponding constraints to the double-punch speed difference.The extrusion with three punch to prepare bending tubes mainly analyzes the rules of theformed bending tube, and give explanation to the bending tube shape and the relationshipbetween the speed differential and the curvature of the bending tube. The law speeddifferential and the curvature is the same to the extrusion with two punch, and the more thescale of the third punch, the bigger the turning angle of the bending tube.The extrusion with four punch to prepare bending tubes, through the inspiration theextrusion of two punch and three punch, set the loading mode, and a very clear space curvedpipe is prepared. The material flowing velocity filed is more complex. We make use of spacevelocity filed to analyze the turning and bending trend of the bending tube, and make a limitto the bending forming, moreover research the quality of the formed tube. Space velocity isthe main factor that causes the tube to bend; this method can prepare a space bending tube which have o good surface.The tubes of different shapes can be prepared by changing the loading mode and thestructure of the die. The extrusion with two punch get a plane bending tube, and The extrusionwith more punch can prepare a space or plane bending tube.