03Lecture-ch13-Calc 3190U

# 03Lecture-ch13-Calc 3190U - Manufacturing Production...

This preview shows pages 1–3. Sign up to view the full content.

3 Chapter 13 - 13.2.2 Analysis of Extrusion Calculations For Plastics What is the flow rate of polymer melt in extruder? Refer to Figure 13.5 in textbook As screw rotates inside barrel, the melt is forced to move forward towards die, this is drag flow . A w A D d A DN Q f c d cos ) tan ( ) cos ( 5 . 0 - = π Q d = volume drag flow rate (m 3 /s, in 3 /s) D = screw diameter (m, in) N = screw rotational speed (rev/s, rev/s) d c = screw channel depth (m, in) A = flight angle = D p A = tan where p = pitch w f = flight land width (m, in) If we assume flight land width is negligibly small then formula simplifies to A A Nd D Q c d cos sin 5 . 0 2 2 = Compressing the melt through downstream die creates back pressure flow . = dl dp A Dd Q c b η 12 sin 2 3 Q b = back pressure flow (m 3 /s, in 3 /s) η = viscosity (N-s/m 2 , lb-sec/in 2 ) 1

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
dp/dl = the pressure gradient (Pa/m, lb/in 2 /in) – stronger at die end, weaker
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 4

03Lecture-ch13-Calc 3190U - Manufacturing Production...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online