Modeling of extrusion-blown molding process of polymeric package

Abstract

Introduction. For achievement of uniform minimum thickness of a wall of the created container and definition of the corresponding technological modes numerical researches of process of hollow polymeric products formation are conducted. Researches are conducted depending on a form of preparation and a finished product.Material and methods. In this work formation process by blowing of an axisymmetric bottle is modeled. Initial workpiece represents a cylindrical sleeve with an external radius of 10 mm. After creation of internal pressure workpiece is blown, the contact between polymer and a blown form will not be provided yet. The research is conducted on the case of formation of products from a polyethylene with low density (LDPE).Results and discussion. When the process of blowing the internal pressure is being modeled, initial thickness and outer diameter of preparation are set as constants. With an increase in the radius of a bottom corner of a bottom a wall thickness increases, however at the same time the product becomes unstable. For ensuring the minimum necessary thickness in this place it is necessary to spend excess material in other sections. Extent of thinning of a wall of a product increases with an increase in extent of blowing on a certain local site. As it follows from the results of modeling, for achievement of the minimum necessary uniform thickness of a product it is necessary to change workpiece thickness on height (in this case - to reduce it in the lower and average parts). This method of calculation of a necessary profile of thickness of preparation allows to reach uniformity of thickness of walls of the product. For this purpose workpiece on height breaks into conditional nodes, in each of which the necessary thickness of workpiece depending on the calculated product wall thickness in the corresponding point is defined by iteration.The interrelation between the workpiece, a finished product and the distribution of thickness in its walls is defined.