Problem VI Coextrusion Blow Molding Die

Extrusion processes involve the use of extruders that melt and pump polymers and shaping devices called dies that are placed at the end of the extruder. This chapter is concerned with the design of extrusion dies while Chapter 8 deals with single- and twin-screw extruders. 

Extrusion dies are metal channels that impart a specific cross-sectional shape to a polymer stream. The design difficulty centers on achieving the desired shape within set limits of dimensional uniformity at the highest production rate possible. Because of the viscoelastic nature of polymers and the associated flow behavior, it is no simple matter to design a die that will produce a smooth extrudate with the desired dimensions. 

Polymer Processing Principles and Design, Second Edition. Donald G. Baird and Dimitris I. ColUas. 2014 Jdm WQey Sons, Inc. Published 2014 by John Wiley Sons, Inc. 

FIGURE 7.1 Cross section of an elliptically shaped parison consisting of HOPE and nylon 6 in a 9 1 ratio by weight. 

Section 7.6. Finally, in Section 7.7, the solution to Design Problem VI is presented. 

---