The development of the extrusion molding die system assisted by the ultrasonic vibrations

摘要

Recently, high precise manufacturing quality of polymer thin films with 470tnrn in width is required to an extrusion molding die system Unfavorable die lines, which are several micron meters higher or lower than other surface and parallel to the extrusion direction are often appeared in the extrusion molding. And these lines give severe damages to the quality of the films. To reduce these lines, the authors proposed an extrusion molding die system assisted by ultrasonic vibrations with 20kHz in frequency. Designing the ultrasonic vibration system is, however, difficult, even if the finite element analysis(FEA) is employed. Because the accurate boundary conditions of the connecting bolt, which are used for supporting the vibration system, cannot be determined accurately. The authors proposed the design method that is a cut and try, one where the appropriate elastic constants of the contact surface connected by bolts are found by comparing a measured vibration data of a trial made extrusion molding tool with a calculation result by FEA of a tool. Then, an ultrasonically assisted extrusion molding tool designed by the proposed method was successfully applied to a manufacturing process line.