Extrusion Introduction An extruder is a common machine in industry ...

5. Calculate the inner diameter (Di) to obtain inner radius (R i ) and thickness (θ) from
Eq. (16) and Eq. (17), respectively.
6. Repeat with several different internal pressures to finish section 3 in Table 1. (Choose
at least 5 different internal pressures.)
7. Plot tube outer and inner radius versus internal pressure and versus theoretical
prediction.
(Note: the diagrams may or may not be linear.)
Notations
u Velocity factor (m/s)
u r-directional component of the velocity vector u (m/s)
w z-directional component of the velocity vector u (m/s)
μ Viscosity of fluid (Pas)
w o Output speed at die exit (m/s)
w L Take-off speed (m/s)
r o Outer radius at die exit (mm)
r i Inner radius at die exit (mm)
R o Outer radius of tube (mm)
R i Inner radius of tube (mm)
p i Internal pressure (pa)
ω Screw rotating speed (rpm)
v t Take-off speed (m/s)
m Mass feeding rate of DYNH-1 (kg/min)
V Volumetric feeding rate of DYNH-1 (m 3 /min)
ρ Density of DYNH-1 (kg/m 3 )
D o Outer diameter of tube (mm)
D i Inner diameter of tube (mm)
θ Thickness of tube (mm)
Reference
Dr. Chang-Won Park, Extrusion of Hollow Tubes
Mark, H. F. (ed.), Encyclopedia of Polymer Science and Technology, Edition 3 rd ., John
Wiley & Sons (2004) (Vol. 2)
Stanley Middleman, Fundamentals of Polymer Processing, McGraw Hill (1977)