ANALYSIS OF THE FREE SURFACE INSTABILITIES IN EXTRUSION AND - - PowerPoint PPT Presentation

Athens, Greece, May 14-16, 2007

ANALYSIS OF THE FREE SURFACE INSTABILITIES IN EXTRUSION AND COEXTRUSION FLOWS FOR METALLOCENE BASED POLYOLEFINS

Polymer Centre, Faculty of Technology Tomas Bata University in Zlin, Czech Republic 3M Belgium N.V. (Dyneon)

Martin Zatloukal, Katerina Chaloupkova, Johan De Witte Jiri Vlcek, Compuplast International, Inc.

OBJECTIVES

• Introduction
• Theoretical and Experimental Investigation
• Concluding Remarks

Multi-manifold coextrusion

• II. converging section

II.

• I. merging area

I. III.

• III. die exit

Free surface problem

CONCLUSION

• 1. It

has been found experimentally that chamfering of the die exit wall under angle α = 15- 45o significantly reduces the die drool phenomenon.

• 2. It has been revealed theoretically that wall slip

reduces the negative pressure at the die exit region which is stabilizing effect from the die drool phenomenon point of view.

• 3. It has been speculated that internal die drool

can be explained by negative pressure inside the die.

• 4. It has been suggested that pressure,

magnitude of the pressure gradient and normal gradient pressure component can be useful variables for theoretical investigation

• f the die drool phenomenon.

ACKNOWLEDGEMENT

Thank you Assoc. Prof. Jiri Vlcek, Dr. Jiri Svabik and

• Dr. Ilja Paseka from Compuplast Int. for many very

fruitful discussions and help with negative pressure idea for die drool onset explanation presented in this work.

THANK YOU FOR YOUR ATTENTION