A NEW NON-CONVENTIONAL CONCEPT FOR DESIGN OF SHEET EXTRUSION DIES

摘要

A new non-conventional die design for extrusion of plastic sheet is introduced. Instead of using a conventional sheet die design, such as the coat-hanger, or fishtail design, a completely non-conventional innovative die geometry was developed to achieve a highly uniform velocity distribution at the die exit (die balancing). While balancing the flow at the die exit, with the new die concept, the pressure drop in the die was reduced to about 29% of the original value, and the sharkskin instability was also eliminated from the extrusion process.