Design of Balance Flow Channel in T-type Extrusion Dies

T-type extrusion dies is a kind of widely-used slot die.According to the present design method for flow channel in die, increasing the radius of the manifold or reducing the thickness of the choke zone was generally adopted to improve the uniformity of the melt exit flow rate along die width direction.However, increasing the radius of manifold increases the residence time of the melt in die, and reducing the thickness of choke zone causes a sharp increase of extrusion pressure, so other measures are demanded to meet requirement in practice.Two choke zones with different thicknesses were adopted to solve the problem.Under the precondition that the melt exit flow rate is uniform along the die width direction, the demarcation carve between the two choke zones were deduced based on rheology.In addition, the traditional T-type dies designing method was compared with the method proposed.The results show that the residence time of the melt can be significantly reduced by using the proposed design method and the flow channel designed through proper selection of radius of manifold, the thickness of the two choke zones and demarcation curve between the two choke zones., and the extrusion pressure can be adjusted according to the processing requirements.Therefore, the proposed design method can be used to guild the design of flow channel in T-type dies. © 2020, Editorial Department, Journal of South China University of Technology. All right reserved.